Hansen on runaway warming
hgerh...@yahoo.co.uk
"In the long run [...] over centuries, we could actually get a runaway
greenhouse effect, and then that's it for all the species on this
planet [...]. [R]unaway greenhouse effect means once the planet gets
warmer and warmer, then the oceans begin to evaporate.[...] [T]he
oceans will begin to boil, and the planet becomes so hot that the
ocean ends up in the atmosphere."
Looking through the archives I found this thread:
http://groups.google.com/group/globalchange/browse_thread/thread/b1138ef9f85f2143/4742d33cac46f2ba?lnk=gst&q=runaway#4742d33cac46f2ba
How come I am posting on this now? Well, I saw a review in the New
Scientist of this book:
http://www.amazon.co.uk/Storms-My-Grandchildren-Catastrophe-Humanity/dp/1408807440/ref=sr_1_2?ie=UTF8&s=books&qid=1262253512&sr=8-2
http://www.newscientist.com/article/mg20427381.700-will-you-stand-up-against-climate-disaster.html
"James Hansen, is telling it as he sees it, and the result is the most
frightening book I have ever read, for three reasons.
First, Hansen has come to believe, based on studies of past climate
change, that the threat facing us is far worse than he thought even a
few years ago. The very survival of life on Earth is at stake, he
says. The sun is 2 per cent brighter than it was just 250 million
years ago, and if we burn up all the fossil fuel on the planet - all
the oil, coal, tar sand and tar shale - we will trigger a runaway
greenhouse effect that will ultimately lead to the oceans boiling
away, he claims."
Alastair
oceans boiled away the earth would be completely covered in cloud.
This would raise the albedo from 0.3 to 0.9 and the planet would cool!
The real danger is that carbon dioxide will melt the Arctic sea ice.
Then the conveyer will halt in the North Atlantic with two
consequences.
1) CO2 will no longer be able to be so readily absorbed in that cold
water so its atmospheric concenration will increase.
2) The cold water will no longer descend to the ocean floor allowing
the methane hydrates to warm and release their methane.
This seems to have happened before during the Triassic-Jurassic mass
extinction and at the PETM methane "belch". So we may ge an extinction
but not an extermination :-)
Cheers, Alastair.
On Dec 31 2009, 10:06 am, "hgerhau...@yahoo.co.uk"
<hgerhau...@yahoo.co.uk> wrote:
> http://bigthink.com/jameshansen/the-science-of-global-catastrophe
>
> "In the long run [...] over centuries, we could actually get a runaway
> greenhouse effect, and then that's it for all the species on this
> planet [...]. [R]unaway greenhouse effect means once the planet gets
> warmer and warmer, then the oceans begin to evaporate.[...] [T]he
> oceans will begin to boil, and the planet becomes so hot that the
> ocean ends up in the atmosphere."
>
> Looking through the archives I found this thread:
> http://groups.google.com/group/globalchange/browse_thread/thread/b113...
>
> How come I am posting on this now? Well, I saw a review in the New
> Scientist of this book:http://www.amazon.co.uk/Storms-My-Grandchildren-Catastrophe-Humanity/...
>
> http://www.newscientist.com/article/mg20427381.700-will-you-stand-up-...
Tom Adams
On Dec 31 2009, 5:06 am, "hgerhau...@yahoo.co.uk"
<hgerhau...@yahoo.co.uk> wrote:
> http://bigthink.com/jameshansen/the-science-of-global-catastrophe
>
> "In the long run [...] over centuries, we could actually get a runaway
> greenhouse effect, and then that's it for all the species on this
> planet [...]. [R]unaway greenhouse effect means once the planet gets
> warmer and warmer, then the oceans begin to evaporate.[...] [T]he
> oceans will begin to boil, and the planet becomes so hot that the
> ocean ends up in the atmosphere."
>
> Looking through the archives I found this thread:
> http://groups.google.com/group/globalchange/browse_thread/thread/b113...
>
> How come I am posting on this now? Well, I saw a review in the New
> Scientist of this book:http://www.amazon.co.uk/Storms-My-Grandchildren-Catastrophe-Humanity/...
>
> http://www.newscientist.com/article/mg20427381.700-will-you-stand-up-...
>
> "James Hansen, is telling it as he sees it, and the result is the most
> frightening book I have ever read, for three reasons.
>
> First, Hansen has come to believe, based on studies of past climate
> change, that the threat facing us is far worse than he thought even a
> few years ago. The very survival of life on Earth is at stake, he
> says. The sun is 2 per cent brighter than it was just 250 million
> years ago, and if we burn up all the fossil fuel on the planet - all
> the oil, coal, tar sand and tar shale - we will trigger a runaway
> greenhouse effect that will ultimately lead to the oceans boiling
> away, he claims."
"I do need to mention one trick, or approximation, that we employed,
so other scientists do not beat me about the head and shoulders." page
153, refers to factoring out O18 concentrations in snow building the
icecaps. Trick was a harmless term when the text of this book was
edited.
hgerh...@yahoo.co.uk
> oceans boiled away the earth would be completely covered in cloud.
> This would raise the albedo from 0.3 to 0.9 and the planet would cool!
I thought William had somewhere stated that even with an atmosphere
out of pure water vapour there could be clear sky areas without
clouds. I cannot find that statement in the group archives so maybe I
mixed things up somehow.
Anyway, is Hansen being misquoted here? Tbe review of his book makes
it sound, as if runaway global warming of the ocean boiling variety is
a certainty, as opposed to a near impossible event.
Let me add a few other thoughts: The oceans are a few km deep. 10m of
water column is a bar. If the oceans were to evaporate, atmospheric
pressure would rise by of the order of a bar for ever 10m of water. At
atmospheric pressure water boils at 100C, at 30 bar it's more like
250C.
I've done some order of magnitude calculations, and, 100m of perfectly
insulated air column can be heated by 200 W/m2 to the surface
temperature of the sun in a few weeks and melting the world's ice
would take a few decades. To get through the first 10 m (doubling
atmospheric pressure and raising world temperature to above 100C)
would also take a few decades under these extreme assumptions (all the
world's insolation going towards evaporating water, the world being
perfectly insulated against heat loss).
So, to get to 100C in 200 years should take a forcing of the order of
50 to 100 W/m2 by my reckoning.
Michael Tobis
on earth, but from my point of view that is hearsay; I've never seen
the calculations.
Venus is cloud covered and this has not prevented a runaway greenhouse there.
The idea that increased column humidity necessarily leads to either
increased cloud cover or increased precipitation is not correct in
itself; you have to appeal to the complexities of the climate system.
(Current evidence is strong that column precipitation increases much
more slowly than column humidity; this has important implications for
the large scale circulation. I don't know what the projections are for
clouds and wouldn't entirely trust them. All of this, though, presumes
conditions much less catastrophic than Hansen is discussing.)
I think it's an unfair summary to say that Hansen is actually
predicting a Venuslike state for the earth; he is simply speculating
upon it under a reporter's questioning. He may be political enough to
be reluctant to say "a runaway greenhouse won't happen". But he didn't
say it will.
Amid all the gloom (which I think and hope is a bit excessive in what
we see of the Hansen interview), I remain amused by the common
grammatical form of earth scientists, the "second person planetary" as
in "But with continued rapid increase in greenhouse gases, you could
melt the ice sheets in less than a century". Who, me?
mt
hgerh...@yahoo.co.uk
> predicting a Venuslike state for the earth; he is simply speculating
> upon it under a reporter's questioning. He may be political enough to
> be reluctant to say "a runaway greenhouse won't happen". But he didn't
> say it will.
I thought that the New Scientist book review sounded not quite right,
but I have not read the book.
> "But with continued rapid increase in greenhouse gases, you could
> melt the ice sheets in less than a century".
Isn't that awfully aggressive?
He is not talking about Greenland here, but about all the world's ice,
70 metres of sea level equivalent of ice.
I have been doing some back of the envelope calculations, like to melt
70 metres of water by mixing it with sea water would require cooling
around 600 metres of water by 10C, or something of the order of three
decades worth of the complete insolation the Earth receives. Or, at
200 W per m2 just for Antarctica alone (say around 10 million square
kilometres) it would take of the order of a thousand years to melt the
ice.
What sort of scenario do you need to get the ice sheets to melt
completely in less than 100 years?
Michael Tobis
disintegrating over a century and that most of the base of Greenland
is above sea level, which it sort of has to be, or it would have
disintegrated already. East Antarctica will not go anywhere for a very
long while.
> I have been doing some back of the envelope calculations, like to melt
> 70 metres of water by mixing it with sea water would require cooling
> around 600 metres of water by 10C, or something of the order of three
> decades worth of the complete insolation the Earth receives. Or, at
> 200 W per m2 just for Antarctica alone (say around 10 million square
> kilometres) it would take of the order of a thousand years to melt the
> ice.
>
> What sort of scenario do you need to get the ice sheets to melt
> completely in less than 100 years?
The west Antarctic ice sheet will not melt. It will fail mechanically
and will float away in bits. Sea level can consequently increase by
meters in a century, and has done so in prior failures of West
Antarctica. "The rise of sea level during meltwater pulse 1A was as
much as 16 meters within 300 years (14.6 to 14.3 thousand years ago)."
http://initforthegold.blogspot.com/2007/08/4-meter-sea-level-rise-precedent.html
Some people seem to believe that some sort of mechanical
disintegration is possible in Greenland, abetted by moulins.
As for your calculations:
If Greenland and WAIS were to melt completely, sea level would rise 12
m. Ocean area is 3.6e14 m^2 http://en.wikipedia.org/wiki/Ocean so the
volume of ice at issue is 4.3e15m^3 or 4.3e15 tons.
Watt-hours to melt a ton of ice:
latent heat of melting = 334 kJ/kg = 3.34e8J/ton = 92778 watt-hour/ton
Total energy to melt the vulnerable ice sheets = 9.28e4 * 4.3e15 =
3.99e20; call it 4e20 watt-hours.
Solar energy at top of atmosphere per meter, average = 330 W /m^2
Total energy impinging on earth = earth area * top of atmosphere solar
constant = 5.1e14m^2 *3.3e2W = 1.6e17 W
Number of hours to melt all ice if the sun did no other work:
4e20/1.6e17 = 2500, or 104 days.
Suppose we only use the excess energy at the surface due to CO2
doubling (feedbacks included), believed to be around 4 W/m^2. Then the
time is multiplied by 330/4 = 206250 hours = 23.5 years.
So it would take about a quarter of the excess energy due to 2xCO2
over a century to melt Greenland and the WAIS. As you point out, some
of the energy will come from thermal energy banked in the ocean rather
than directly from the sun.
But I am not getting numbers comparable to yours. To go from my 12 m
to your 70 requires a factor of only 6, meaning it would require the
complete solar input for 624 days.
While I agree you could not in practice melt the main Antarctic ice
mass in a century, we are in disagreement by a factor of 15 if I
understand you correctly.
mt
hgerh...@yahoo.co.uk
> to your 70 requires a factor of only 6, meaning it would require the
> complete solar input for 624 days.
Your number of days is of the right magnitude, I thought the
spreadsheet calculation was so easy I would not make a silly mistake,
but well I did.
I think the 4 W/m2 for CO2 do not include the water vapour and cloud
feedbacks. So, for quadrupled CO2 (Hansen talks about all fossil fuels
being burnt) we've got twice that plus feedbacks. For a climate
sensitivity of 3C, the feedbacks are about a factor three. 4*2*3= 24 W/
m2
being available from CO2 four times pre-industrial.
And there dies my idea that all the ice melting in less than a century
(as suggested by Hansen) is close to what the enthalpy of melting
would allow. It might still be an out of this world notion, but then
for some other reason.
James Annan
> I think the 4 W/m2 for CO2 do not include the water vapour and cloud
> feedbacks. So, for quadrupled CO2 (Hansen talks about all fossil fuels
> being burnt) we've got twice that plus feedbacks. For a climate
> sensitivity of 3C, the feedbacks are about a factor three. 4*2*3= 24 W/
> m2
> being available from CO2 four times pre-industrial.
I haven't followed all of the calculation in detail, but this is wrong.
It doesn't matter what the feedbacks are, 2xCO2 is still only 4W/m^2.
What the feedbacks do is change the amount by which the outgoing
radiation changes as the planet warms.
James
hgerh...@yahoo.co.uk
> It doesn't matter what the feedbacks are, 2xCO2 is still only 4W/m^2.
> What the feedbacks do is change the amount by which the outgoing
> radiation changes as the planet warms.
I am not sure what Michael means with "feedbacks included" on
reflection.
I am also not entirely sure what you are saying here, but I think it's
probably that the greenhouse gas water vapour is temperature dependent
and if all of the 4 W per m2 from CO2 go towards melting ice, then
none is available for increasing Earth's temperature and therefore the
concentration of water vapour stays contstant.
James Annan
I'm just saying the energy imbalance is capped at 4W for a doubling of
CO2 (and will reduce as the planet warms) irrespective of sensitivity.
James
Robert A. Rohde
observation that it hasn't happened yet. Most of Earth's history has
had higher CO2 levels than today without triggering a Venus-like
runaway. The Earth has been as high as ~2000 ppmv CO2 in the last 150
million years, and ~5000 ppmv during the last 500 million. Even if
you burn all the declared fossil fuel reserves on Earth you'd have a
hard time finding enough to go much past 1000 ppmv, so it is quite
unlikely that we could reach a state that exceeded the natural
variation during the recent geologic past. Hence, history indicates
that the climate avoids a Venus-like runaway under the foreseeable
concentrations humans are likely to create.
On very long time scales, some evidence suggests CO2 concentrations
may have been as high as 1 bar at 3.5 billion years ago, though at
that time the atmosphere would have been very different and solar
luminosity only 70% of modern.
-Robert Rohde
Alastair
same conclusion as you, that a boiling away of the oceans was
impossible for the same reasons you give, in this paper:
Pierrehumbert, R. T. 1995: Thermostats, Radiator Fins, and the Local
Runaway Greenhouse. J. Atmos. Sci. 52, 1784-1806.
http://geosci.uchicago.edu/~rtp1/papers/JASRadiatorFins.pdf
I think he also deals with Wiiliam's point which I imagine was that
clouds only form in rising air, and since what goes up must come down,
then only 50% of the surface can have rising air and be covered in
clouds. Logical, but not true of Venus!
Cheers, Alastair.
On Jan 2, 4:29 pm, "hgerhau...@yahoo.co.uk" <hgerhau...@yahoo.co.uk>
wrote:
Igor Samoylenko
From: "hgerh...@yahoo.co.uk" <hgerh...@yahoo.co.uk>
To: globalchange <global...@googlegroups.com>
Sent: Sat, 2 January, 2010 16:29:22
Subject: [Global Change: 3383] Re: Hansen on runaway warming
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Alastair
On Jan 2, 11:52 pm, Igor Samoylenko <samoylen...@yahoo.co.uk> wrote:
> Hansen mentioned the Venus syndrome in his Bjerknes Lecture he gave at AGU in December 2008:
>
> http://www.columbia.edu/~jeh1/2008/AGUBjerknes_20081217.pdf
Thanks for that link :-)
>
> What he said is this:
> Now the danger that we face is the Venus syndrome. There is no escape from the Venus Syndrome. Venus will never have oceans again.
Hansen seems to believe that Venus had oceans, but that is now seeming
unlikely. It is now thought that Earth's oceans were formed from
impacts from Main Asteroid Belt Comets.
http://www.solstation.com/stars/asteroid.htm
These are icy outer asteroids which had there orbits distorted by
Jupiter. As their orbits became more elliptical, they collided with
Earth, which protected Venus and kept it dry. The runaway state of
Venus's atmosphere must be due to CO2, not H2O!
Cheers, Alastair.
Tom Adams
> The best argument against a runaway greenhouse on Earth is the
> observation that it hasn't happened yet.
Because the Sun did not put out as much energy in the past as it does
these days, according to Hansen in his new book.
Hansen's runaway senario involves burning all the fossil fuels, even
the tar sand, BTW.
Tom Adams
> On Jan 2, 11:52 pm, Igor Samoylenko <samoylen...@yahoo.co.uk> wrote:
>
> > Hansen mentioned the Venus syndrome in his Bjerknes Lecture he gave at AGU in December 2008:
>
> >http://www.columbia.edu/~jeh1/2008/AGUBjerknes_20081217.pdf
>
> Thanks for that link :-)
>
>
>
> > What he said is this:
> > Now the danger that we face is the Venus syndrome. There is no escape from the Venus Syndrome. Venus will never have oceans again.
>
> Hansen seems to believe that Venus had oceans, but that is now seeming
> unlikely. It is now thought that Earth's oceans were formed from
> These are icy outer asteroids which had there orbits distorted by
> Jupiter. As their orbits became more elliptical, they collided with
> Earth, which protected Venus and kept it dry.
Really? Do you think Earth ran around like a short stop and caught
them all? How the heck could little ole Earth's cross-section
(relative to the vastness of its obital cross secton) protect Venus?
Phil Hays
> Hansen seems to believe that Venus had oceans, but that is now seeming
> unlikely. It is now thought that Earth's oceans were formed from
> impacts from Main Asteroid Belt Comets.
> http://www.solstation.com/stars/asteroid.htm
> These are icy outer asteroids which had there orbits distorted by
> Jupiter. As their orbits became more elliptical, they collided with
> Earth, which protected Venus and kept it dry. The runaway state of
> Venus's atmosphere must be due to CO2, not H2O!
A scale model might help to visualize.
If the Earth is a peppercorn, then the Sun is a 20 cm ball about 26
meters away. Get a peppercorn and a ball, and make a scale model of the
Earth/Sun system. If you please, you could also add Venus another
peppercorn 19 meters from the Sun, and the Earth's Moon, a bit of gravel
2 cm away from the Earth. Now imagine that there are comets coming from
the outer solar system, in the neighborhood of Jupiter, another 110
meters beyond the Earth.
Just how many of these comets will the Earth prevent from hitting Venus?
--
Phil Hays <phil...@ieee.org>
Robert A. Rohde
Go back 500 million years, and solar luminosity is only about 7% lower
than now but CO2 was 20 times higher. I have trouble believing that
the small increases in solar luminosity could have left us so
precariously balanced on the edge of a knife that we'd just now be on
the brink of a Venus-like runaway. I'd also add that many points in
that same 500 million year span had deglaciated polar caps, and
average global temperatures about 10 C warmer than today. Which
further suggests that you have to have quite substantial warming
before you get outside the range of past natural variation and can
start to worry about a new kind of runaway.
I don't know that a Venus-style run away is impossible for Earth, but
I think it is so improbable (and so many other bad things would have
to happen first) that even bringing it up in a serious discussion of
global warming consequences seems misleading. It smacks of fear-
mongering, provides skeptics with a talking point that is easy to
criticize, and distracts from the quite substantial consequences of
global warming that are far more probable.
-Robert Rohde
James Annan
Perhaps my previous message was not as clear as it could have been. On
an initial doubling of CO2, the imbalance is 4W/m^2 before there are any
other changes. As the atmosphere warms, the water vapour increases but
the radiative imbalance *decreases* anyway, because the warmer
atmosphere is closer to radiative equilibrium (ie outgoing LW radiation
increases). A high sensitivity just means that the disequilibrium
decreases slowly as the temp increases. If the disequilibrium actually
increased with warming, the system would be unstable.
James
James Annan
> You may be interested to hear that Prof. Ray Pierrehumbert came to the
> same conclusion as you, that a boiling away of the oceans was
> impossible for the same reasons you give, in this paper:
>
> Pierrehumbert, R. T. 1995: Thermostats, Radiator Fins, and the Local
> Runaway Greenhouse. J. Atmos. Sci. 52, 1784-1806.
> http://geosci.uchicago.edu/~rtp1/papers/JASRadiatorFins.pdf
Thanks for the ref. I wondered if his name would come up, as he has said
similar things on RC.
GCMs can achieve runaway warming - in fact some informal conversations
suggest to me that this is rather more common than you might imagine
based on reading the literature - but this is generally attributed to
some nonphysical behaviour such as a parameterisation extrapolated
beyond its valid range. However, I don't believe that Pierrehumbert's
handwaving with simple approximations can really refute calculations of
state of the art climate models.
Nevertheless a the strong argument against it, as Robert Rohde
mentioned, is that the Earth has been up to ~3000ppm in the past and
recovered.
James
Alastair
> Phil Hays <phil_h...@ieee.org>
What is described by Jewitt is main-belt comets, but these are not the
main comets, and Jewitt estimates there may be only 150. They are in
the main asteroid belt. What is being proposed is that the water on
the Earth came from icy asteroids which formed further than the main
asteroid belt from the Sun and closer to Jupiter. They arn't there now
because they have all crashed into Mars and Earth.
Cheers, Alastair.
Alastair
On Jan 3, 9:57 pm, Tom Adams <tadams...@yahoo.com> wrote:
> Really? Do you think Earth ran around like a short stop and caught
> them all? How the heck could little ole Earth's cross-section
> (relative to the vastness of its obital cross secton) protect Venus?
Earth would not act as a backstop to regular comets coming from the
the Oort and Kuiper belts, but if the Main (asteroid) Belt Comets,
with circular orbit gradually became more elliptical they would crash
with Earth first, and not become elliptical enough to crash with
Venus. These are asteroids that formed beyond the snowline. Of course
icy asteroids forming further from the snowline would be more likely
to be disturbed by Jupiter and crash into Earth.
http://www2.ess.ucla.edu/~jewitt/papers/2006/F06.pdf
Here is a news release which is a little more explicit:
http://www.hawaii.edu/news/article.php?aId=1379
Note, a couple of telling points. Earth formed within the snowline so
it should have been dry. The H/D ratio of Earth's water does not match
that of comets, or of meteoric water from the Earth's mantle. The late
heavy bombardment has not yet been explained, but could have been
caused by the adjustment of the orbits Jupiter and Saturn disrupting
the orbits of the outer asteroids which were beyond the snowline. See
also:
http://www.ifa.hawaii.edu/~meech/NAIJC/papers/gaidos_jc2.pdf
Here's a list of Jewitt's publications, which will be useful if you
want to follow this up.
http://www2.ess.ucla.edu/~jewitt/bib.html
Not sure if that will convince you, but it makes sense to me.
Cheers, Alastair.
James Annan
I don't know much about planetary evolution, but I've read enough to
know that there are some pretty counterintuitive (to me) things going
on, mostly due to the amazingly long time scales involved.
In this case it doesn't seem too implausible that if the comets are
slowly nudged into increasingly elliptical orbits, they will almost
invariably get caught by the Earth before the orbit becomes sufficiently
distorted to reach Venus. But I'm just guessing really.
James
hgerh...@yahoo.co.uk
> an initial doubling of CO2, the imbalance is 4W/m^2 before there are any
> other changes. As the atmosphere warms, the water vapour increases but
> the radiative imbalance *decreases* anyway, because the warmer
> atmosphere is closer to radiative equilibrium (ie outgoing LW radiation
> increases). A high sensitivity just means that the disequilibrium
> decreases slowly as the temp increases. If the disequilibrium actually
> increased with warming, the system would be unstable.
I was looking at the forcing multiplier, as if it could happen without
the concurrent temperature increase. That's very unreasonable for a
smooth temperature forcing function, and not so unreasonable with a
tipping point, where suddenly cloud cover or relative moisture
changes.
Without tipping point like changes, I suppose a lot less than 4 W/m2
is actually available averaged over 100 years to melt ice, as most
will go towards warming the upper ocean waters and as the imbalance
decreases as the temperature goes up.
On the other hand, using all the 4 W/m2 pretty much implies a tipping
point like change. The temperature of the Earth stays constant thanks
to all the melt water and still the ice is suddenly melting, when
before it was not.
hgerh...@yahoo.co.uk
> than now but CO2 was 20 times higher.
I think that we need to be careful when drawing conclusion from past
climate. At least for the last million years we've got very reliable
measurements for CO2 concentrations, but before that we are dealing
with proxy evidence. In addition, the overall forcing presumably
matters, not just the CO2 related forcing, and with regards to
aerosols or surface albedo we know awfully little.
Furthermore, a factor 20 for CO2 is not actually that far from a
quadrupling, as it might appear at first, because of the logarithmic
relationship. The forcing from a quadrupling is 8 W/m2, from a factor
16, 16 W/m2.
Let me say a bit more about surface albedo. All it takes for surface
albedo to have been lower 500 million years ago would for example be
for widespread algae to colour the ocean water slightly brighter. Or
cloudiness could have been different due to widespread sulphate
aerosol emissions from bacteria.
Granted this is all a bit handwavy, but when you talk about
vanishingly small probabilities, and base this on climate history, I
think the evidence needs to be pretty solid. Likewise, I think
Hansen's talk of certainty is pushing it, the same logarithmic
relationship applies there, so even if he's talking 2000 or 3000 ppm,
oil sands included, it's not that different from 1000 ppm.
Kooiti MASUDA
> Hansen mentioned the Venus syndrome in his Bjerknes Lecture he gave at AGU in December 2008:
>
> http://www.columbia.edu/~jeh1/2008/AGUBjerknes_20081217.pdf
>
> What he said is this:
In the chapter 10 'Venus syndrome' of his book 'Storms of my
Grandchildren',
Hansen says similar thing.
But, as far as I understand, he does not properly formulate here
what is the condition for runaway greenhouse effect, or 'Venus
syndrome'.
What he shows with good scientific support is that the climate system
is
more sensitive to radiative forcing (either solar constant or CO2)
at both warmer and colder extremes, due to greenhouse effect of water
vapor
and ice-albedo feedback, respectively. I think this is reasonable.
Then he suggests that even CO2 level of 1000 ppm may be dangerous
(this corresponds to "10-20 W/m2" in the Bjerknes lecture, I guess),
perhaps first triggering such an event like Paleocene-Eocene Thermal
Maximum
and then Venus-like runaway greenhouse (evaporation of the ocean).
But he does not tell how likely will it be, or how confident he is.
(This is a complaint a la Stephen Schneider. I know it is a tall
order.)
As far as I understand, the value 1000 ppm is just an estimate of the
maximum
level of CO2 in the atmosphere in the Cenozoic era except PETM.
I could not grasp why he considers this level is near the runaway
situation.
So I am tempted not to use Hansen's book as a reliable source about
climate
change (though it is still a very interesting book).
*****
By the way, some attempts to simulate runaway greenhouse condition in
GCM
are here (information for experts of climate dynamics):
Ishiwatari M., Takehiro S.-I., Nakajima K., Hayash Y.-Y., 2002:
A numerical study on appearance of the runaway greenhouse state of a
three-dimensional gray atmosphere.
Journal of Atmospheric Sciences, 59, 3223-3238.
DOI:10.1175/1520-0469(2002)059<3223:ANSOAO>2.0.CO;2
Ishiwatari M., Nakajima K., Takehiro S., Hayashi Y.-Y., 2007:
Dependence of climate states of gray atmosphere on solar constant:
From the runaway greenhouse to the snowball states.
J. Geophys. Res., 112, D13120, doi:10.1029/2006JD007368.
http://www.agu.org/pubs/crossref/2007/2006JD007368.shtml
(subscription needed for full text)
Note that their formulation of radiative processes was crude.
Probably they wanted to focus in dynamics.
Ko-1 M. (Kooiti Masuda)
Alastair
Yes, as the major axis increases due to the gravitational pull of
Jupiter, the minor axis decreases until it reaches 1AU, then crash!
The major axis rather than the minor will increase because that is
when the asteroid is on the corresponding part of the ellipse that it
is nearest Jupiter, and so Jupiter has a greater gravitational
effect. A sort of positive feedback!
BTW I misunderstood the term "Main Belt". It refers to the whole of
the Asteroid Belt, not a part of it. It is used to distinguish
objects in the Asteroid belt from those in the Kuiper and Oort belts.
However, that does not negate the theory. The outer asteroids in the
Main Belt tend to be icy, and they are the ones that are most affected
by Jupiter, so it is logical that they would be the cause of the Late
Heavy Bombardment. http://en.wikipedia.org/wiki/Late_Heavy_Bombardment
Note, this is all 21st Century science, dating back only to 1999.
Cheers, Alastair.
Tom Adams
> On Jan 3, 9:57 pm, Tom Adams <tadams...@yahoo.com> wrote:
>
> > Really? Do you think Earth ran around like a short stop and caught
> > them all? How the heck could little ole Earth's cross-section
> > (relative to the vastness of its obital cross secton) protect Venus?
>
> Earth would not act as a backstop to regular comets coming from the
> the Oort and Kuiper belts, but if the Main (asteroid) Belt Comets,
> with circular orbit gradually became more elliptical they would crash
> with Earth first, and not become elliptical enough to crash with
> Venus. These are asteroids that formed beyond the snowline. Of course
> icy asteroids forming further from the snowline would be more likely
>
> Here is a news release which is a little more explicit:http://www.hawaii.edu/news/article.php?aId=1379
> Note, a couple of telling points. Earth formed within the snowline so
> it should have been dry. The H/D ratio of Earth's water does not match
> that of comets, or of meteoric water from the Earth's mantle. The late
> heavy bombardment has not yet been explained, but could have been
> caused by the adjustment of the orbits Jupiter and Saturn disrupting
> the orbits of the outer asteroids which were beyond the snowline. See
> also:http://www.ifa.hawaii.edu/~meech/NAIJC/papers/gaidos_jc2.pdf
>
> Here's a list of Jewitt's publications, which will be useful if you
>
> Not sure if that will convince you, but it makes sense to me.
>
> Cheers, Alastair.
I guess that might make it plausible.
But the references you cite say nothing about Venus being protected.
Hansen cites hydrogen isotope evidence from the current atmosphere of
Venus that it once had lots of water:
http://www.pas.rochester.edu/~blackman/ast104/vatmosphere.html
Phil Hays
> Yes, as the major axis increases due to the gravitational pull of
> Jupiter, the minor axis decreases until it reaches 1AU, then crash!
The Earth has a much bigger "gravity well" than surface area. If a comet
or other body comes close, then the Earth's gravity will much more
likely deflect it into a different orbit than there be an impact. This
different orbit might be an Earth impacting one, or also might be a
Venus impacting one, but is more likely going to have multiple close
passages with one or more planets before any impact, or before ejection
from the solar system.
--
Phil Hays <phil...@ieee.org>
Alastair
Well, he would say that wouldn't he? :-)
http://en.wikipedia.org/wiki/Mandy_Rice_Davies#.22Well_he_would.2C_wouldn.27t_he.3F.22
I presume you are referring to this:
=======================================
Absence of Water Vapor
The clouds contain little water vapor, and there is little evidence
for water in any form on Venus. It is speculated that the absence of
water is because most water that may have initially been on Venus made
its way to the upper atmosphere where it was broken down by sunlight
and interactions with cosmic rays and the solar wind into oxygen and
hydrogen, which was then lost to interplanetary space.
There are several reasons to believe this. First, there is evidence
that there was a lot of water on Venus at one time. This comes form
Pioneer spacecraft observations which showed 150 times more DEUTERIUM
(heavy isotope of hydrogen) per hydrogen atom than on Earth. This
deuterium naturally forms from the dissociation of water (H20) into
its respective components hydrogen and oxygen.
Because deuterium is a heavier isotope of hydrogen (having 1 neutron
in the nucleus in addition to just the proton) it rises more slowly in
the atmopshere. Thus the lighter isotope of hydrogen largely escaped
but the heavier isotope remained. This provides evidence that there
was more water on Venus. Enough to make a surface covering ocean about
25 meters deep.
The reason that the UV radiation could penetrate the atmosphere is
because the oxygen was not able to form ozone but instead mainly
formed oxides in the soil.
======================================
The evidence of higher levels of HDO on Venus than Earth cuts both
ways. The level of HDO on earth is similar to that on Mars, in carbon
chondrite meteorites, and so presumably in icy asteroids. It is
higher than Kuiper belt comets, and even higher in Oort belt comets.
So it would seem that the high HDO level on Venus is due to its
proximity to the sun, where the gravitational effects raised the
levels of the heavier HDO molecules. The values on the Earth would
have been similar but for the input from the Main Belt Comets.
The idea that the ozone layer would have protected water vapour on
Earth from being disassociated is not convincing. The ozone layer
only formed after the atmosphere became oxidized which was half way
through its life at around 2200 Ma. Moreover, the ozone layer resides
in the stratosphere and disassociation happens above the mesosphere,
so the ozone layer could not protect the water vapour there.
However, the stratosphere (ozone layer) does trap the water vapour
below it, so without an ozone layer it might be possible for the water
vapour to convect up to mesospheric altitudes. However I doubt even
that, since CO2 also absorbs solar radiation and so it would form an
inversion layer trapping the water vapour below the region of
dissociation.
Occam's Razor suggests that the Earth's water comes from icy MLB
comets since it is likely that their HDO ratios match.
But that's enough from me,
Cheers, Alastair.
Alastair
Well, I can't prove that it happened. Nor AFAIK can anyone.
But I saw an estimate of 5000 times the amount of water on Earth,
formed in the asteroid belt. So we ca let a few of the passing MLB
comets crash into Mars, the Sun, Jupiter, and off to space and still
have enough left over to fill the Earth. Mars is smaller than Earth,
and may only have served to help protect Venus rather than protect
Earth. In other words, even if Earth or Mars did not collide with the
comets they would probably distort their orbits enough to make a
collision with Venus unlikely.
But a model is required, and much more data.
Cheers, Alastair.
Tom Adams
Venus from icy asteroids?
You can find discussions and explanations of the number of craters on
Venus, but I can't find any that mention the protective effect of the
Earth. Seems an odd omission if there is a protective effect.
> Well, he would say that wouldn't he? :-)http://en.wikipedia.org/wiki/Mandy_Rice_Davies#.22Well_he_would.2C_wo...
> Cheers, Alastair.- Hide quoted text -
>
> - Show quoted text -
Igor Samoylenko
From: Kooiti MASUDA <mas...@jamstec.go.jp>
To: globalchange <global...@googlegroups.com>
Sent: Mon, 4 January, 2010 11:00:23
Subject: [Global Change: 3410] Re: Hansen on runaway warming
Alastair
On Jan 5, 1:06 pm, Tom Adams <tadams...@yahoo.com> wrote:
> Can you cite something, anything, that claims that Earth protected
> Venus from icy asteroids?
>
> You can find discussions and explanations of the number of craters on
> Venus, but I can't find any that mention the protective effect of the
> Earth. Seems an odd omission if there is a protective effect.
I did try to find where I first heard of Earth's water being delivered
by the icy asteroids, but have failed. The first citation I gave was
obtained with a quick Google search in order to justify my
(surprising) statement.
Venus is dry, and it may have occurred to me that Earth intercepting
the asteroids would explain that dryness, but as I recall it was given
as a reason for the dryness of Venus. If I can find my original source
I will at least be able to confirm or deny whether it does claim that.
BTW, the lack of evidence of for the Late Heavy Bombardment at 3,800
Ma (old craters) on Venus cannot be due to a shielding by Earth. It
is because Venus was resurfaced around 700 Ma, so even if the old
craters formed they would not be there now.
Also, I found this at http://www.space.com/scienceastronomy/090105-mm-venus-water.html
deagleninja wrote:
"I would think our relatively giant moon would help us capture many
more icy comets throughout our early history than Venus. It's presence
extends the gravitational effect of our system an additional quarter
million miles does it not?"
Of course at 3,800 Ma it would have extended the radius by less than
the current 250,000 miles.
OTOH, we are talking about asteroids that start out close to Jupiter.
As the major axis of the asteroid was extended, the asteroid might
have reached Jupiter before the minor axis was small enough for it to
reach Venus. In that case, would Jupiter be the frontstop? It may be
easy to check with the right data, whether the asteroid could mmet
earth but not Venus before reaching Jupiter. We know roughly the
initial solar orbits of the icy asteroids - greater than 3 AU to
Jupiter's 5 AU and Venus at 0.723 AU.
Cheers, Alastair
Phil Hays
> OTOH, we are talking about asteroids that start out close to Jupiter.
> As the major axis of the asteroid was extended, the asteroid might
> have reached Jupiter before the minor axis was small enough for it to
> reach Venus. In that case, would Jupiter be the frontstop? It may be
> easy to check with the right data, whether the asteroid could mmet
> earth but not Venus before reaching Jupiter. We know roughly the
> initial solar orbits of the icy asteroids - greater than 3 AU to
> Jupiter's 5 AU and Venus at 0.723 AU.
This is a matter of gravity(1). The gravity of Jupiter will always be
perturbing the orbits of everything else in the solar system. To learn
more, I would suggest downloading a gravity simulator and try some
experiments with asteroids with orbits like these.
Intuition doesn't work well on orbital physics. For example: Going
faster makes your orbit slower. Slowing down usually increases your
average velocity. Having an orbit that exactly intercepts another body's
orbit means that there may not be a collision (unless both bodies are
small enough, or the relative velocity is high enough, or some special
cases).
It has been a long time since I spent a lot of time with an orbital
simulator, and the only one I could recommend first hand you would
probably have a lot of trouble getting to work on a modern computer.
However, Google searching for "gravity simulator" gives this as the
first hit:
http://www.orbitsimulator.com/
I have not tried it, but it looks both very user friendly and useful.
Some very nice examples are included.
If you want Linux or MacOSX you might try:
If you want something research grade, but expect to spend a lot more
time learning about the subject, this (and some of the others referenced
from this) looks hopeful:
http://bima.astro.umd.edu/nemo/
A day or a week or so playing with orbits should help anyone to
understand this subject better.
(1) No pun intended.
--
Phil Hays <phil...@ieee.org>
Alastair
On Jan 5, 1:06 pm, Tom Adams <tadams...@yahoo.com> wrote:
> Can you cite something, anything, that claims that Earth protected
> Venus from icy asteroids?
Following from my previous post, it is not that Earth acted as a
backstop. It is that the eccentricity only extended the orbits inwards
as far Earth.
I have found a paper which may have been the first I read about this:
Nature 435, 466-469 (26 May 2005) | doi:10.1038/nature03676; Received
6 December 2004; Accepted 18 April 2005
Origin of the cataclysmic Late Heavy Bombardment period of the
terrestrial planets
R. Gomes1,2, H. F. Levison2,3, K. Tsiganis2 & A. Morbidelli2
It says on page 467:
"However, our scheme probably also produced an in flux of material
from the asteroid belt. As Jupiter and Saturn moved from 1:2 MMR
towards their current positions, secular resonances (which occur when
the orbit of an asteroid processes at the same rate as a planet) swept
across the entire belt. These resonances can drive asteroids onto
orbit with eccentricities and inclinations large enough to allow them
to evolve into the inner Solar System and hit the Moon."
From that I assumed that the inclinations were large enough to hit
Earth but not large enough to hit Venus.
Cheers, Alastair.
matt andrews
(as well as water) was delivered by comets rather than volcanoes:
http://www.sciencedaily.com/releases/2009/12/091210153538.htm
hgerh...@yahoo.co.uk
> A numerical study on appearance of the runaway greenhouse state of a
> three-dimensional gray atmosphere.
> Journal of Atmospheric Sciences, 59, 3223-3238.
> DOI:10.1175/1520-0469(2002)059<3223:ANSOAO>2.0.CO;2
http://dennou-q.gfd-dennou.org/arch/prepri/2002/jas/bousou/pub/runaway.pdf
Looking at the paper I see that with initial temperatures below 300K
there's no runaway, with temperatures around 300K and higher there is.
It's very simplified and all, but still it's an interesting result.
Looking at past temperature history, we think that the Earth was up to
around 10C warmer in the past. I am not sure what the uncertainty on
that is, but it looks like 300K is very much at the high side of
what's credible.
What do we need to get to around 300K? Of the order of 10 to 15 K on
top of pre-industrial. With a climate sensitivity of around 3C, that's
of the order of 10 to 20 W/m2.
So, I can see where Hansen gets that ballpark figure from.
Robbo
another global apocalypse scenario - but do take everything on the
human knowledge site with a bucket of salt. Lucky we only have to
wait to 2012 for the end of the universe (LOL).
There is a new theory of climate that is a little more serious -
http://www.nosams.whoi.edu/PDFs/papers/tsonis-grl_newtheoryforclimateshifts.pdf
- it goes beyond the simple physics of gases and radiation to the
modern physics of complex systems. It views climate on decadal
timescales as an emergent property of complex and dynamic Earth
systems. There are all sorts of future possibilities - including
extremes. The ultimate 'strange attractors' seem to be states +/- 10
degrees C but being definitive beyond next month seems theoretically
impossible. Correlation certainly won't work as there is no simple
cause and effect.
Chaos theory explains why it hasn't warmed in the past decade. Thus
is the battle lost and it may take another generation or 2 to take any
action...
I am, at any rate, missing the point of science that needs to be
definitive and have scary answers. This is particularly the case
where science is synthesis rather than hypothesis and experiment.
There are three real human questions about climate.
1. Should we continue to change the composition of the atmosphere? No.
2. What is the cheapest and most effective way to transition
economies? I call this the organisational and technological path - it
is said by economist Bjorn Lomborg's Copenhagen Consensus Group to be
300 times more cost effective than cap and trade methods.
Organisational methods could include such things as this geo-
engineering proposal for carbon sequestration involving afforestation
of deserts in Africa and Australia. A mega project in greening the
Sahel has potential not only to sequester carbon but to bring safe
water, sewerage, power, education and health services to the heart of
Africa. The proposal would have some ecological show stoppers in
Australia - but a project to restore carbon stores to pre-European
levels in Australian soils has as well productivity, fire risk and
conservation benefits. It is easily possible to do something other
than an inefficient, complex and market distorting government imposed
limit on carbon emissions. This latter approach seems to stem in
good part from a sincere desire, based on the limits to growth of the
Club of Rome or similar, to reduce global wealth to some ostensibly
sustainable level. An approach likely to be counter productive with
respect to both population and conservation. Population growth
declines and environmental standards increase with increasing
GDP.
There are a number of technologies that are available and in use, are
10 years or less away or can be delivered within 20 years. Thin (and
therefore cheap) solar panels are a dream source for many of the
world's poorest who don't have adequate energy supplies. Generation 4
nuclear plants have a 40 year development history and are being built
and operated now. A new model designed at Los Alamos - the US
government laboratory famous (or infamous) for the first atomic bomb -
will be available commercially from 2013. Generation 4 nuclear plants
can't melt down, are modular and flexible, can't be used for weapons
production, use a range of nuclear materials (conventional nuclear
waste, uranium, thorium and recycled weapons plutonium) providing
virtually limitless fuels, burn two orders of magnitude more
efficiently than conventional reactors and create much shorter lived
wastes (hundreds of years rather than hundreds of millennia). Endless
energy for endless purposes through clever fuel processing and
materials. The Gen 4 International Forum - which Australia should
join given our huge nuclear fuels advantage - has a technology roadmap
for 6 different designs for different purposes to be delivered by
2030. In the interim there are Gen 3 and 3+ technologies to go on
with. These are perfectly adequate in many locations and applications
- and indeed there are hundreds of these plants ordered or under
construction.
Geothermal, wind farms, solar concentrators, algal biofuels, oil
recovery from waste, co-generation, carbon efficiency, coal to gas
conversion, coal seam methane production to name a few more examples.
There are technologies available now that are cost effective and
others where costs are coming down and technologies are improving.
This is not market magic - but the inevitable outcome of the rapid
rate of technological innovation. Instead of spending $400 billion on
carbon regulation - spend, mostly by the private sector, a fraction of
that on research and development and create better and cheaper energy
options for the world.
Technology and organisation having changed the trajectory - science
(successfull in the job of provisionally warning) can return to being
fun explorations of the universe around us. I am particularly fond of
trying to reconcile evolutionary theory with the space/time continuum
but some people just don't have a sense of humour.
3. What does the science say?
http://www.sciencedaily.com/releases/2008/12/081218094605.htm
'The Sun not only emits light and heat into space, it constantly spews
out solar wind, a stream of charged particles. This solar wind carries
electrical and magnetic fields throughout the Solar System and ‘blows’
past the planets.
Unlike Earth, Venus does not generate a magnetic field. This is
significant because Earth’s magnetic field protects its atmosphere
from the solar wind. At Venus, however, the solar wind strikes the
upper atmosphere and carries off particles into space. Planetary
scientists think that the planet has lost part of its water in this
way over the four-and-a-half-thousand million years since the planet’s
birth.
“We do see water escaping from the night-side but the question
remains, how much has been lost in the past in this way,” says Stas
Barabash, Swedish Institute of Space Physics, Kiruna and Principal
Investigator of ASPERA, that looked at night-side data.
While the earth retains oceans and an atmosphere - there are the
ultimate feedbacks of the hydrological cycle and the Stefan-Boltzmann
relationship. Vapour will rise in the atmosphere and radiate at
increasing intensities (exponentially to the 4th power)as the planet
warms - an intensification of the hydrological cycle such as we have
seen since the climate shift of the mid 1970's.
I think runaway warming is just one more problem too far. I would
have one thing to say to James Hansen - with all my love - don't worry
it will be 2012 very soon. I wonder why Venus doesn't have a magnetic
field? Is it something to do with the core materials?
Cheers
Robbo
On Jan 6, 3:59 am, Igor Samoylenko <samoylen...@yahoo.co.uk> wrote:
> I have not read his book yet but from what I can see so far it is indeed difficult to justify his level of certainty (from his lecture):
>
> "All Coal ->?? (Runaway Possible)
> Coal + Tars ->!! (Dead Certainty)"
>
> With all due respect to James Hansen (and I do have tremendous respect for him as a scientist), it is hard not to take this view as an outlier amongst the climate scientists.
>
> I wonder if he is using the same approach here as in his paper on sea level rise "Scientific reticence and sea level rise"?:http://www.iop.org/EJ/article/1748-9326/2/2/024002/erl7_2_024002.html
>
> "Is my perspective on this problem really so different than that of other members of the
> relevant scientific community? Based on interactions with others, I conclude that there is
> not such a great gap between my position and that of most, or at least much, of the
> relevant community. The apparent difference may be partly a natural reticence to speak
> out, [...]"
>
> That may be the case with the sea level rise but has any climate scientists come out to support him in his views on the possibility of the Venus-type runaway greenhouse effect here on Earth?
>
> PS: According to one of the links cited by Robbo (http://humanknowledge.net/Thoughts.html):
>
> "Global Warming. Accumulation of greenhouse gases is causing a rise in global temperature of a few degrees celsius. This may by 2050 melt enough antarctic ice to raise sea levels by a few feet and cause some coastal flooding. Warming may make weather cycles more extreme but may also make land more useful in the northern expanses of Asia and North America. Projected greenhouse warming is not severe enough to lead to runaway effects like on Venus."
>
> So, that is OK then :-)
>
> The next quote though casts some doubt over the credibility of this site (as far as climate science is concerned at least):
>
> "Ice Age. When Earth's next ice age arrives in 10,000 years or so, [...]."
>
> Yeah, right...
>
> A few more quotes for your entertainment:
>
> "Timeline
> ...
> 2020Almost all overt tyranny has been eliminated.
> ...
> 2030Radio astronomers have discovered signals from extraterrestrial intelligence."
Tom Adams
There are currently a good many asteroids known to have Venus crossing
obits:
http://en.wikipedia.org/wiki/List_of_Venus-crossing_minor_planets
Planets and asteroids don't all orbit in the same plane. The planets
obital planes vary by 1-7 degrees. Obits are elliptical and not in
the same plane, so the probability of Earth colliding with a Earth-
crossing asteroid can can be small or even zero:
"An asteroid with an Earth-crossing orbit is not necessarily in danger
of colliding with the Earth, far from it. The orbit of an Earth-
crossing asteroid may not even intersect with the orbit of the Earth.
This apparent contradiction arises because many asteroids have highly
inclined orbits, so although they may have a perihelion less than that
of the Earth, their paths can never cross."
Alastair
Science 28 April 2006:
Vol. 312. no. 5773, pp. 535 - 536
DOI: 10.1126/science.1126896
Perspectives
PLANETARY SCIENCE:
Ice Among the Rocks
Alan Fitzsimmons*
At the same time, Hsieh and Jewitt [2006] note that the outer asteroid
belt has been proposed as a source of the water deposited on Earth
after the end of the planet-building phase. This work should spur a
closer assessment of recent dynamical models predicting delivery of
large numbers of objects from this region into near-Earth space
[Gomesl et al. 2005]. It is interesting that many astronomers have
pursued comets to greater and greater distances in their pursuit of
understanding the evolution of comets and the early history of the
solar system. All this time, it would have also been worthwhile to
look a little closer to home.
> > R. Gomes1, H. F. Levison, K. Tsiganis & A. Morbidelli
> > Nature 435, 466-469 (26 May 2005) | doi:10.1038/nature03676; Received
> > 6 December 2004; Accepted 18 April 2005
>
> > Origin of the cataclysmic Late Heavy Bombardment period of the
> > terrestrial planets
> There are currently a good many asteroids known to have Venus crossing
> obits:
Yes, but they are probably dead comets from beyond Jupiter and the
results of asteroid collisions.
> Planets and asteroids don't all orbit in the same plane. The planets
> obital planes vary by 1-7 degrees. Obits are elliptical and not in
> the same plane, so the probability of Earth colliding with a Earth-
> crossing asteroid can can be small or even zero:
In general, any existing asteroid with and Earth-crossing orbit is not
going to hit the earth now, since it has been missing us for 4.600
billion years! In other words, Earth crossing asteroids are the the
exceptions that prove the rule.
The orbital inclination of Venus is 3 23', Earth 0 0', Mars 1 52', and
Jupiter 1 18'. From that it appears that Venus and Earth are equally
likely to receive collisions from an asteroid with an inclination
roughly equal to that of Jupiter/Mars.
I've run http://www.orbitsimulator.com/ (Thanks Phil :-) with one
asteroid that had an orbit greater than any at present but less than
that of Jupiter. Its orbits slowly filled the space between Mars and
Jupiter, and probably would have continued to fill the space as far as
Earth. Left longer yet it could have reached Venus, but if it had
already collided with Mars or Earth that would not happen.
What is being suggested is that the outer Main Belt asteroids are
carbonaceous chondrites, containing 30% water with a similar D/H ratio
to that of Earth's water. Beyond that are the the newly discovered
Main Belt comets with a dirty exterior and an icy interior, say 50%
water perhaps with the same D/H ratio. Beyond that were the icy
asteroids with say 75% water with the same D/H ratio. Because they
were too close to Jupiter, their orbits became more elliptical until
they collided with Earth. In fact, it was the resonance of Jupiter
with Saturn that disturbed these icy asteroids, and their orbits would
have changed from circles into strange attractors, not ellipses.
This is still speculation, but it does mean that Venus need not have
had oceans like Earth.
Cheers, Alastair.
Nolin, Kenneth M.
December 26, 2009 · 236 comments
guest article by John O'Sullivan
For any non-scientist interested in the climate debate, there is nothing better than a ready primer to guide you through the complexities of atmospheric physics - the "hardest" science of climatology. Here we outline the essential points made by Dr. Gerhard Gerlich, a respected German physicist, that counter the bogus theory of Anthropogenic Global Warming (AGW).
Before going further, it's worth bearing in mind that no climatologist ever completed any university course in climatology-that's how new this branch of science really is. Like any new science the fall-back position of a cornered AGW proponent is the dreaded "appeal to authority" where the flustered debater, out of his or her depth, will say, "Well, professor so-and-so says it's true - so it must be true." Don't fall for that proxy tree-ring counter's gambit any longer. Here is the finest shredding of junk science you will ever read.
In a recently revised and re-published paper, Dr Gerlich debunks AGW and shows that the IPCC "consensus" atmospheric physics model tying CO2 to global warming is not only unverifiable, but actually violates basic laws of physics, i.e. the First and Second Law of Thermodynamics. The latest version of this momentous scientific paper appears in the March 2009 edition of the International Journal of Modern Physics.
The central claims of Dr. Gerlich and his colleague, Dr. Ralf Tscheuschner, include, but are not limited to:
1) The mechanism of warming in an actual greenhouse is different than the mechanism of warming in the atmosphere, therefore it is not a "greenhouse" effect and should be called something else.
2) The climate models that predict catastrophic global warming also result in a net heat flow from atmospheric greenhouse gasses to the warmer ground, which is in violation of the second law of thermodynamics.
Essentially, any machine which transfers heat from a low temperature reservoir to a high temperature reservoir without external work applied cannot exist. If it did it would be a "perpetual motion machine" - the realm of pure sci-fi.
Gerlich's and Tscheuschner's independent theoretical study is detailed in a lengthy (115 pages), mathematically complex (144 equations, 13 data tables, and 32 figures or graphs), and well-sourced (205 references) paper. The German physicists prove that even if CO2 concentrations double (a prospect even global warming advocates admit is decades away), the thermal conductivity of air would not change more than 0.03%. They show that the classic concept of the glass greenhouse wholly fails to replicate the physics of Earth's climate. They also prove that a greenhouse operates as a "closed" system while the planet works as an "open" system and the term "atmospheric greenhouse effect" does not occur in any fundamental work involving thermodynamics, physical kinetics, or radiation theory. All through their paper the German scientists show how the greenhouse gas theory relies on guesstimates about the scientific properties involved to "calculate" the chaotic interplay of such a myriad and unquantifiable array of factors that is beyond even the abilities of the most powerful of modern supercomputers.
The paper's introduction states it neatly:
(a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.
This thorough debunking of the theory of man made warming disproves that there exists a mechanism whereby carbon dioxide in the cooler upper atmosphere exerts any thermal "forcing" effect on the warmer surface below. To do so would violate both the First and Second Laws of Thermodynamics. As there is no glass roof on the earth to trap the excess heat, it escapes upward into space.Thus we may conclude that the common sense axioms are preserved so that the deeper the ocean, the colder the water and heat rises, it does not fall. QED.
John O'Sullivan is a legal advocate and writer who for several years has litigated in government corruption and conspiracy cases in both the US and Britain. Visit his website.
Eric Swanson
On Jan 6, 10:50 pm, Robbo <rob...@robertellison.com.au> wrote:
> I was looking for a source for heat pollution - it seems to be just
> another global apocalypse scenario - but do take everything on the
> human knowledge site with a bucket of salt. Lucky we only have to
> wait to 2012 for the end of the universe (LOL).
>
> There is a new theory of climate that is a little more serious -http://www.nosams.whoi.edu/PDFs/papers/tsonis-grl_newtheoryforclimate...
> - it goes beyond the simple physics of gases and radiation to the
> modern physics of complex systems. It views climate on decadal
> timescales as an emergent property of complex and dynamic Earth
> systems. There are all sorts of future possibilities - including
> extremes. The ultimate 'strange attractors' seem to be states +/- 10
> degrees C but being definitive beyond next month seems theoretically
> impossible. Correlation certainly won't work as there is no simple
> cause and effect.
>
> Chaos theory explains why it hasn't warmed in the past decade. Thus
> is the battle lost and it may take another generation or 2 to take any
> action...
>
> I am, at any rate, missing the point of science that needs to be
> definitive and have scary answers. This is particularly the case
> where science is synthesis rather than hypothesis and experiment.
Robo guy, posting such long winded repeats of earlier rants is not
likely to endear you with the moderators. Your fixation on bhe papers
by Tsonis just shows your lack of understanding. The various indices
which Tsonis et al. use don't cause anything, they just capture the
variation in the weather patterns. There is no reason to assume that
they are the only forces acting on the climate system, indeed we know
of several external forcings which are time variant. Without
understanding causality, it's a fools game to jump into prediction.
Chaos "theory" doesn't explain why there are correlations between the
indices.
For example, tell us what you think the NAO means? Let's also hear
your discussion of the THC process and potential for variation.
E. S.
Tom Adams
> German Physicists Trash Global Warming "Theory"
> December 26, 2009 · 236 comments
>
> guest article by John O'Sullivan
>
> For any non-scientist interested in the climate debate, there is nothing better than a ready primer to guide you through the complexities of atmospheric physics - the "hardest" science of climatology. Here we outline the essential points made by Dr. Gerhard Gerlich, a respected German physicist, that counter the bogus theory of Anthropogenic Global Warming (AGW).
>
> Before going further, it's worth bearing in mind that no climatologist ever completed any university course in climatology-that's how new this branch of science really is. Like any new science the fall-back position of a cornered AGW proponent is the dreaded "appeal to authority" where the flustered debater, out of his or her depth, will say, "Well, professor so-and-so says it's true - so it must be true." Don't fall for that proxy tree-ring counter's gambit any longer. Here is the finest shredding of junk science you will ever read.
>
> In a recently revised and re-published paper, Dr Gerlich debunks AGW and shows that the IPCC "consensus" atmospheric physics model tying CO2 to global warming is not only unverifiable, but actually violates basic laws of physics, i.e. the First and Second Law of Thermodynamics. The latest version of this momentous scientific paper appears in the March 2009 edition of the International Journal of Modern Physics.
>
> The central claims of Dr. Gerlich and his colleague, Dr. Ralf Tscheuschner, include, but are not limited to:
>
> 1) The mechanism of warming in an actual greenhouse is different >than the mechanism of warming in the atmosphere, therefore it is not >a "greenhouse" effect and should be called something else.
True, greenhouses block convection, whereas greenhouse gases
retransmit radiation. But, the fact that we call it by the wrong
name means nothing.
>
> 2) The climate models that predict catastrophic global warming also >result in a net heat flow from atmospheric greenhouse gasses to the >warmer ground, which is in violation of the second law of >thermodynamics.
>
> Essentially, any machine which transfers heat from a low >temperature reservoir to a high temperature reservoir without >external work applied cannot exist. If it did it would be >a "perpetual motion machine" - the realm of pure sci-fi.
This is true for heat transfer via conduction. Greenhouse gases work
via retransmitting radiation.
For instance, you can concentrate radiation from the sun with a
parbolic mirror. But the mirror is much cooler than the object where
the radiation is concentrated. This is possible because the mirror is
reflecting radiation, not conducting heat, to the hot object.
>
> Gerlich's and Tscheuschner's independent theoretical study is detailed in a lengthy (115 pages), mathematically complex (144 equations, 13 data tables, and 32 figures or graphs), and well-sourced (205 references) paper. The German physicists prove that even if CO2 concentrations double (a prospect even global warming advocates admit is decades away), the thermal conductivity of air would not change more than 0.03%. They show that the classic concept of the glass greenhouse wholly fails to replicate the physics of Earth's climate. They also prove that a greenhouse operates as a "closed" system while the planet works as an "open" system and the term "atmospheric greenhouse effect" does not occur in any fundamental work involving thermodynamics, physical kinetics, or radiation theory. All through their paper the German scientists show how the greenhouse gas theory relies on guesstimates about the scientific properties involved to "calculate" the chaotic interplay of such a myriad and unquantifiable array of factors that is beyond even the abilities of the most powerful of modern supercomputers.
>
> The paper's introduction states it neatly:
>
> (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.
>
> This thorough debunking of the theory of man made warming disproves that there exists a mechanism whereby carbon dioxide in the cooler upper atmosphere exerts any thermal "forcing" effect on the warmer surface below. To do so would violate both the First and Second Laws of Thermodynamics. As there is no glass roof on the earth to trap the excess heat, it escapes upward into space.Thus we may conclude that the common sense axioms are preserved so that the deeper the ocean, the colder the water and heat rises, it does not fall. QED.
>
> John O'Sullivan is a legal advocate and writer who for several years has litigated in government corruption and conspiracy cases in both the US and Britain. Visit his website.
>
>
>
> -----Original Message-----
> From: global...@googlegroups.com [mailto:global...@googlegroups.com] On Behalf Of Alastair
> Sent: Wednesday, January 06, 2010 2:33 PM
> To: globalchange
> Subject: [Global Change: 3420] Re: Hansen on runaway warming
>
> On Jan 5, 1:06 pm, Tom Adams <tadams...@yahoo.com> wrote:
> > Can you cite something, anything, that claims that Earth protected
> > Venus from icy asteroids?
>
> Following from my previous post, it is not that Earth acted as a backstop. It is that the eccentricity only extended the orbits inwards as far Earth.
>
> I have found a paper which may have been the first I read about this:
> Nature 435, 466-469 (26 May 2005) | doi:10.1038/nature03676; Received
> 6 December 2004; Accepted 18 April 2005
>
> Origin of the cataclysmic Late Heavy Bombardment period of the terrestrial planets
>
> R. Gomes1,2, H. F. Levison2,3, K. Tsiganis2 & A. Morbidelli2
>
> It says on page 467:
>
> "However, our scheme probably also produced an in flux of material from the asteroid belt. As Jupiter and Saturn moved from 1:2 MMR towards their current positions, secular resonances (which occur when the orbit of an asteroid processes at the same rate as a planet) swept across the entire belt. These resonances can drive asteroids onto orbit with eccentricities and inclinations large enough to allow them to evolve into the inner Solar System and hit the Moon."
>
> From that I assumed that the inclinations were large enough to hit Earth but not large enough to hit Venus.
>
matt andrews
the barrel.
Full rebuttal here:
(doc) http://groups.google.com/group/rabett-run-labs/web/G%26T_rebuttal-2-6.doc?hl=en
(pdf) http://groups.google.com/group/rabett-run-labs/web/G%26T_rebuttal-2-6.pdf?hl=en
The wonder is that the International Journal of Modern Physics B
published this rubbish.
2010/1/8 Nolin, Kenneth M. <KMN...@fbd.com>:
Robbo
There is no need to be rude. I keep trying to find a way to
communicate a difficult concept in modern physics involving complex
systems as it relates to climate.
‘The climate system is particularly challenging since it is known that
components in the system are inherently chaotic; there are feedbacks
that could potentially switch sign, and there are central processes
that affect the system in a complicated, non-linear manner. These
complex, chaotic, non-linear dynamics are an inherent aspect of the
climate system.’ (IPCC TAR s14.2.2.1 - http://www.ipcc.ch/ipccreports/tar/wg1/504.htm)
‘Modern climate records include abrupt changes that are smaller and
briefer than in paleoclimate records but show that abrupt climate
change is not restricted to the distant past.’ (Abrupt Climate
Change: Inevitable Surprises, 2002, NAP, p19 -
http://books.nap.edu/openbook.php?record_id=10136&page=19).
The Tsonis et al theory of ocean/climate states
http://www.nosams.whoi.edu/PDFs/papers/tsonis-grl_newtheoryforclimateshifts.pdf)
confirms that climate on decadal timescales is an emergent property of
complex and dynamic Earth systems. "You go from a cooling regime to a
warming regime or a warming regime to a cooling regime. This way we
were able to explain all the fluctuations in the global temperature
trend in the past century," Anastasios Tsonis said.
The methodology has nothing at all to do with correlation or
causality. 'First we construct a network from four major climate
indices. The network approach to complex systems is a rapidly
developing methodology, which has proven to be useful in analyzing
such systems’ behavior [Albert and Barabasi, 2002; Strogatz, 2001]. In
this approach, a complex system is presented as a set of connected
nodes. The collective behavior of all the nodes and links (the
topology of the network) describes the dynamics of the system and
offers new ways to investigate its properties. The indices represent
the Pacific Decadal Oscillation (PDO), the North Atlantic Oscillation
(NAO), the El Niño/Southern Oscillation (ENSO), and the North Pacific
Oscillation (NPO) [Barnston and Livezey, 1987; Hurrell, 1995; Mantua
et al., 1997; Trenberth and Hurrell, 1994]. These indices represent
regional but dominant modes of climate variability, with time scales
ranging from months to decades. NAO and NPO are the leading modes of
surface pressure variability in northern Atlantic and Pacific Oceans,
respectively, the PDO is the leading mode of SST variability in the
northern Pacific and ENSO is a major signal in the tropics. Together
these four modes capture the essence of climate variability in the
northern hemisphere. Each of these modes involves different mechanisms
over different geographical regions. Thus, we treat them as nonlinear
sub-systems of the grand climate system exhibiting complex dynamics.'
The NAO is strongly negative and this may be a decadal variation
leading to very much cooler conditions over the NH. The Bermuda-
Labrador Basin Transport Index is near it's low point in the very
limited record. A strong cooling - as is being seen in the current NH
winter - may continue. It has happened in the past century - it is
very possible that NH (particularly US, northerly regions of Europe
and the Arctic) temperatures will fall strongly over the next decade
or 2.
The SOI is sharply down and negative - indicating a return to La Nina
in the SH fall. This will lead to sharply lower global temps and
proportionately greater SH falls. The SAM index is positive but the 1
year tendency is to lower values. The SAM decadal tendency is to
negative values and sharply cooler SH conditions. The PDO is negative
of course and this is a decadal variation that is related to ENSO
frequency and duration - more frequent and intense La Nina in the
negative mode. This contributed to the lack of global warming over the
last decade which may intensify over the next decade or two.
ENSO and PDO have large impacts on global temperature because they
involve interactions between the deep ocean and the surface. More
cold upwelling results in cooler temperatures. More upwelling happens
when the oceans cool a little - perhaps as a result of cloud changes -
I refer you to the Project Earthshine site for a discussion of Earth
albedo changes. ENSO is also related to the Antarctic Polar Vortex.
Stratospheric ozone over the poles warms and cools as a result of
variation in solar UV in turn affecting the strength of the polar
vortex and thus surface flows along Antarctic Peninsula to the western
coast of South America. This in turn influences the thermal evolution
of the Humboldt Current and ENSO. Part of a complex web of
interacting global systems.
The indices are not indicative of any causal agency but do capture
modes of climate variability and associated effects. It is like
saying that the PDO and ENSO cause changes in decadal patterns of
rainfall in Africa, Australia, Asia, the USA and South America. But
the underlying cause is not PDO or ENSO but the dynamics of climate as
a forced nonlinear oscillator expressing in part as the PDO and
ENSO.
Chaos theory confirms the reality of the risk of serious climate
change (either warming or cooling) in response to greenhouse gas
forcing. In the short term however (a decade or so), surface
temperature may continue on the current trajectory of a lack of
warming.
Most people always think they have the complete and unvarnished
truth. The usual state of the human condition is more or less
complete ignorance. Indeed the best definition of science I know of
is that science is exploration at the boundary of human ignorance. It
is a hard lesson learned time and time again.
Cheers
Robbo
Eric Swanson
With all due respect to you and your civil engineering experience, I
think you have missed my point.
Robbo wrote:
> The Tsonis et al theory of ocean/climate states
> http://www.nosams.whoi.edu/PDFs/papers/tsonis-grl_newtheoryforclimateshifts.pdf)
> confirms that climate on decadal timescales is an emergent property of
> complex and dynamic Earth systems. "You go from a cooling regime to a
> warming regime or a warming regime to a cooling regime. This way we
> were able to explain all the fluctuations in the global temperature
> trend in the past century," Anastasios Tsonis said.
From which you conclude:
> The methodology has nothing at all to do with correlation or causality.
But, as Tsonis states:
"[5] Figure 1a shows the distance as a function of time for a window
length of Dt = 11 years, with tick marks corresponding to the year in
the middle of the window. The correlations (and thus distance values
for each year) were computed based on the annual-mean indices
constructed
by averaging the monthly indices over the period of November–March.
The dashed line parallel to the time axis in Figure 1a represents the
95% significance level associated with the null hypothesis that the
observed indices are sampled from a population of a 4-dimensional AR-1
process driven by a spatially (cross-index) correlated Gaussian noise;
the parameters of the AR-1 model and the covariance matrix of the
noise are derived from the full time series of the observed indices.
This test assumes that the variations of the distance with time seen
in Figure 1a are due to sampling associated with a finite-length (11-
yr) sliding window used to compute the local distance values.
Retaining overall cross-correlations in constructing the surrogates
makes this test very stringent. Nevertheless, we still find five times
(1910s, 1920s, 1930s, 1950s, and
1970s) when distance variations fall below the 95% significance level.
We therefore conclude that these features are not likely to be due to
sampling limitations but they represent statistically significant
synchronization events."
In other words, the "proof" of their technique is statistical
correlations. And, they use an 11 year moving average to define their
indices. Moving averages induce spurious "signals" into a time series
thru aliasing. I think that using a moving average thusly may
invalidate their results.
> The NAO is strongly negative and this may be a decadal variation
> leading to very much cooler conditions over the NH. The Bermuda-
> Labrador Basin Transport Index is near it's low point in the very
> limited record. A strong cooling - as is being seen in the current NH
> winter - may continue. It has happened in the past century - it is
> very possible that NH (particularly US, northerly regions of Europe
> and the Arctic) temperatures will fall strongly over the next decade
> or 2.
This does not answer my question. You asserting some future course
for the weather with no link to causality, with no mention of the
historical forcings. To me, such a claim is poor science.
Think of it this way. Build a time series of hourly temperature for
summer. Now, try and "predict" the next full year's temperatures
using Tsonis approach. Will you be able to come anywhere near the
temperatures in winter? Without a full understanding of the rest of
the yearly cycles, such as the yearly solar cycle, you can't come
close to reality. Even with several years of hourly data, you will
still find that such a prediction will miss reality quite a few
times.
> The indices are not indicative of any causal agency but do capture
> modes of climate variability and associated effects. It is like
> saying that the PDO and ENSO cause changes in decadal patterns of
> rainfall in Africa, Australia, Asia, the USA and South America. But
> the underlying cause is not PDO or ENSO but the dynamics of climate as
> a forced nonlinear oscillator expressing in part as the PDO and
> ENSO.
You are assuming that ALL the variation is captured by these indices
and that this variation is the result of the presumed internal
oscillators. The indices don't cause anything, they are just
indicators of the changes in what is measured. They are not
predictive, since they are not based on any changes which may be
occurring in the external forcing, such as solar variability, volcanic
eruptions, additions of greenhouse gases, etc. Tsonis et al. do not
even attempt to remove the external forcings from their indices before
concluding that they have a handle on the internal oscillations.
> Chaos theory confirms the reality of the risk of serious climate
> change (either warming or cooling) in response to greenhouse gas
> forcing. In the short term however (a decade or so), surface
> temperature may continue on the current trajectory of a lack of
> warming.
Again, you make a projection of the future climate based on an
assertion that chaos "theory" will provide a framework to make this
projection. At the moment, it's not clear what might be causing the
slow down in warming, from my limited understanding. It might turn
out that the increased emissions of sulfates and other forms of air
pollution in China and India may be the reason or it may also be that
there is a reduction in the THC in the North Atlantic as a result of
Global Warming. We know both are happening. Can your chaos theory
pick out these possible causes? I think not, since the process is
backward looking and ignores the various forcings.
> Most people always think they have the complete and unvarnished
> truth. The usual state of the human condition is more or less
> complete ignorance. Indeed the best definition of science I know of
> is that science is exploration at the boundary of human ignorance. It
> is a hard lesson learned time and time again.
Sounds reasonable to me. Try telling that to the religious
fundamentalists. So, what does that have to do with your continual
ranting about Tsonis et al.? You are acting like a troll, repeatedly
posting your latest world view for ego gratification or what ever
reasons. Perhaps you should take a bit more time to study the
atmospheric sciences before you start jumping up and down and shouting
"This is IT!!"
E. S.
---
Robbo
I have recently read this paper. The central claim involves the 2nd
law of thermodynamics - that is heat flows from the warmer to the
cooler. It is claimed that the various Earth energy budgets are
incorrect because they involve energy flows from a cooler atmosphere
to a warmer surface. It is indeed the case that AGW theory (and it is
not the case that there is any comparison with a real greenhouse - but
this was always only a metaphor)involves increased radiation downwards
from the atmosphere. There is increased radiation from a warmer
molecule in the atmosphere in all directions - an exponential increase
to the 4th power in accordance with the Stefan-Boltzmann
relationship. But this does not imply a breach of the 2nd Law of
Thermodynamics unless there is a net flow of energy (and therefore
heat) from the cooler to the warmer. The latter does not apply in any
of the energy budgets.
Proving that that the atmosphere is not an actual greenhouse is
pointless and the claim of a voilation of the 2nd law is wrong.
The 1st law is the energy conservation law - energy cannot be created
or destroyed merely transformed. The basis of global energy balances
but not relevant here.
Apply you own criterion and don't take it on faith. There is
radiation from the surface to the atmosphere and back radiation from
the atmosphere down - but the net energy flow is upward from the
surface in all of the energy budgets (and in the models) as it must be
in accordance with the 2nd law.
It is wrong - but be assured that the responses here show a less than
than considered understanding of science as well.
Robbo
I am indeed a civil engineer with a masters in environmental science.
My basic interest is in hydrological science - rainfall and runoff,
water quality, fluvial systems, etc - all of which of course involve
ocean states and atmospheric transport. I have been diligently
searching for an answer to Australian hydrological variability for
more than 20 years. I have found it but I don't know what it means or
what to do with it. Frustrating.
When you say correlation you are thinking in terms of cross
correlation of TSI with temperature for instance - a forcing with an
effect. In the Tsonis case the correlation is of the topological
'distance' between indices. It is more like the autocorrelation
technique used by Dakos et al to examine abrupt climate change in the
past. Autocorrelation is used to discern a repeating pattern in a
signal.
'Slowing down as an early warning signal for abrupt climate change':
Vasilis Dakos, Marten Scheffer, Egbert H. van Nes, Victor Brovkin,
Vladimir Petoukhov, and Hermann Held
14308–14312:PNAS:September 23, 2008:vol. 105:no. 38
You reject complex system dynamics but I quote the IPCC and the NAP as
well in support of the view of climate as a dynamic complex system on
all scales from ENSO to ice ages and beyond. But these are just words
and one needs something of an understanding of the background theory
to understand what these words mean in context. Chaos theory and
strange attractors are indeed central to concepts of abrupt and large
climate change.
I don't say anything about the future in black and white terms - but
the indices I mentioned in response to your question have implications
for climate and weather. For instance, the SAM index and the NAO
index have implications for the tracks of storms spinning off the
polar vortices. The PDO is associated with multidecadal modulation of
ENSO - with obvious implications for climate.
There are a large number of ocean/climate indices -
http://ioc-goos-oopc.org/state_of_the_ocean/all/ - these allow
qualitative judgements about regional rainfall and climate on
interrannual to multidecadal scales to be made without considering
solutions to the Navier-Stokes partial differential equations.
I guess you are the 31.07 year old software engineer known as E-dawg?
I guess that your problem is not with the idea under discussion of
abrupt climate change - so much as what no warming for a decade or 2
will do with what's left of the public debate.
Impossible to predict - the risk of abrupt climate change would
ideally lead to decarbonising economies (and I suggested some means of
doing this that avoids much of the cap and trade downside) but I very
much fear that scientific arrogance, extreme scenarios such as the one
under discussion and green overreach has lost the public relations
battle for a generation or 2.
Regardless of my views - there is no need to be rude and
aggressive.
Cheers
Robbo
On Jan 9, 8:30 am, Eric Swanson <e_swan...@skybest.com> wrote:
> Robbo,
>
> With all due respect to you and your civil engineering experience, I
> think you have missed my point.
>
> Robbo wrote:
> > The Tsonis et al theory of ocean/climate states
> >http://www.nosams.whoi.edu/PDFs/papers/tsonis-grl_newtheoryforclimate...)
Eric Swanson
> Eric,
>
> I am indeed a civil engineer with a masters in environmental science.
I noticed that...
> When you say correlation you are thinking in terms of cross
> correlation of TSI with temperature for instance - a forcing with an
> effect. In the Tsonis case the correlation is of the topological
> 'distance' between indices. It is more like the autocorrelation
> technique used by Dakos et al to examine abrupt climate change in the
> past. Autocorrelation is used to discern a repeating pattern in a
> signal.
Yes, Tsonis uses correlation coefficient in defining their analysis.
See the definition of their so-called "distance", d(t), defined using
the cross-correlation coefficient, rho,i,j(t). But you previously
wrote that they didn't use correlations. I assume that you now agree
with me...
> 'Slowing down as an early warning signal for abrupt climate change':
> Vasilis Dakos, Marten Scheffer, Egbert H. van Nes, Victor Brovkin,
> Vladimir Petoukhov, and Hermann Held
>
> 14308–14312:PNAS:September 23, 2008:vol. 105:no. 38
Isn't this a bit of a red herring? Aren't you shifting the discussion
away from Tsonis, et al.??
And old trick, I must say. BTW, the recent NH winter weather looks
like things are speeding up..
> You reject complex system dynamics but I quote the IPCC and the NAP as
> well in support of the view of climate as a dynamic complex system on
> all scales from ENSO to ice ages and beyond. But these are just words
> and one needs something of an understanding of the background theory
> to understand what these words mean in context. Chaos theory and
> strange attractors are indeed central to concepts of abrupt and large
> climate change.
No, I don't reject such analysis. I just don't think the work of
Tsonis et al. means as much as they (and you) would have us believe.
> I don't say anything about the future in black and white terms - but
> the indices I mentioned in response to your question have implications
> for climate and weather. For instance, the SAM index and the NAO
> index have implications for the tracks of storms spinning off the
> polar vortices. The PDO is associated with multidecadal modulation of
> ENSO - with obvious implications for climate.
>
> There are a large number of ocean/climate indices -
> http://ioc-goos-oopc.org/state_of_the_ocean/all/ - these allow
> qualitative judgements about regional rainfall and climate on
> interrannual to multidecadal scales to be made without considering
> solutions to the Navier-Stokes partial differential equations.
But such indices do not provide meaningful projections of a changing
climate, since the underlying forcings are changing as we know.
> I guess you are the 31.07 year old software engineer known as E-dawg?
Not, although I did work as a scientific programmer for several years
after grad school.
> I guess that your problem is not with the idea under discussion of
> abrupt climate change - so much as what no warming for a decade or 2
> will do with what's left of the public debate.
The so-called debate has degenerated into little more than name
calling on the part of the denialist. They (like you) offer little
substantive discussion, while falling back on unfounded assertions and
repeating unproven and often debunked claims.
> Regardless of my views - there is no need to be rude and
> aggressive.
Well, I don't think I'm the one being aggressive as you have been the
poster of several similar long winded comments praising Tsonis, et al.
without considering the problems in their analysis.
> Cheers
> Robbo
E. S.
---
Phil Hays
> In general, any existing asteroid with and Earth-crossing orbit is not
> going to hit the earth now, since it has been missing us for 4.600
> billion years! In other words, Earth crossing asteroids are the the
> exceptions that prove the rule.
Ever been to Meteor (Barringer) Crater, in Arizona USA? It is an
impressive sight. Or hear anything about the strange geology under the
Yucatan? Or under Chesapeake Bay? There are more than 150 identified
craters on the Earth's surface, and most of them are less than a billion
years old. So why didn't these hit the Earth during the previous 3.600+
billion years? In the case of the Chesapeake crater, how did it miss for
4.565 billion years?
Orbits change. Asteroid orbits can change slowly, by perturbation and
more subtle processes, and rapidly with a near passage to a planet, or
even near passage to one of the more massive asteroids (Ceres, Pallas,
Vesta, and a dozen others). Planet orbits change as well.
> I've run http://www.orbitsimulator.com/ (Thanks Phil :-) with one
> asteroid that had an orbit greater than any at present but less than
> that of Jupiter. Its orbits slowly filled the space between Mars and
> Jupiter, and probably would have continued to fill the space as far as
> Earth. Left longer yet it could have reached Venus, but if it had
> already collided with Mars or Earth that would not happen.
Glad you like it. Running one orbit is interesting, but if you would
like to get a better understanding, try some close passages, both of
Jupiter and other planets. These might be even more interesting. Don't
use just one asteroid, run 10 or more with very slightly different
starting parameters. If they stay clumped, try again, getting closer to
the planet, or perhaps just simulate for more time.
--
Phil Hays <phil...@ieee.org>
Robbo
in science of all sorts. Global shifts in temperature, rainfall, the
'Great Pacific Climate Shift' of 1976/1977, the instrumental
temperature record. As indicated in the 2002 panel discussion of the
National Academy. Tsonis et al have the virtue (in peer reviewed
studies) of using numerical techniques to quantify. The numerical
technique was not concerned with cause and effect - or cross
correlation in the accepted sense - but in detecting patterns in
signals. A network methodology as in the quote I provided earlier.
Show me the papers disputing Tsonis - not simply your frankly silly
claim that because they didn't factor out ENSO and volcanos from ENSO
and other signals that the studies are invalidated.
I sure I don't have a clue what you mean by 'speeding up'. The
concept is that small changes in initial conditions triggers large
flucuation in climate which then oscillates about a new state for a
while. The oscillations tend to damp out (but not neccessarily)in
complex systems providing a signal of the next shift.
I link to the UNESCO site that provides ready access to indices that
are updated by thousands of scientists around the world. And you
simply accuse me of provising unjustified claims - a knee jerk no it
just ain't so. Show me the science damn it. Your claim that these
indices are not relevant because of global warming is unreflective
nonsense. Somehow ENSO and the like have no relevance for
understanding climate? Please.
You are just being foolish now.
> >http://ioc-goos-oopc.org/state_of_the_ocean/all/- these allow
Alastair
On Jan 9, 5:47 am, Phil Hays <phil_h...@ieee.org> wrote:
> On Thu, 2010-01-07 at 13:48 -0800, Alastair wrote:
> > In general, any existing asteroid with and Earth-crossing orbit is not
> > going to hit the earth now, since it has been missing us for 4.600
> > billion years! In other words, Earth crossing asteroids are the the
> > exceptions that prove the rule.
>
> Ever been to Meteor (Barringer) Crater, in Arizona USA? It is an
> impressive sight. Or hear anything about the strange geology under the
> Yucatan? Or under Chesapeake Bay? There are more than 150 identified
> craters on the Earth's surface, and most of them are less than a billion
> years old. So why didn't these hit the Earth during the previous 3.600+
> billion years? In the case of the Chesapeake crater, how did it miss for
> 4.565 billion years?
>
> Orbits change. Asteroid orbits can change slowly, by perturbation and
> more subtle processes, and rapidly with a near passage to a planet, or
> even near passage to one of the more massive asteroids (Ceres, Pallas,
> Vesta, and a dozen others). Planet orbits change as well.
I probably did not explain that very well :-) I think what I should
have said is that using Earth crossing asteroids (i.e. ones that miss
the Earth) as examples of ones that collide is fraught with logical
difficulties. No, maybe I should not have said that either :-
( Forget I ever mentioned the matter, please.
> > I've runhttp://www.orbitsimulator.com/(Thanks Phil :-) with one
> > asteroid that had an orbit greater than any at present but less than
> > that of Jupiter. Its orbits slowly filled the space between Mars and
> > Jupiter, and probably would have continued to fill the space as far as
> > Earth. Left longer yet it could have reached Venus, but if it had
> > already collided with Mars or Earth that would not happen.
>
> Glad you like it. Running one orbit is interesting, but if you would
> like to get a better understanding, try some close passages, both of
> Jupiter and other planets. These might be even more interesting. Don't
> use just one asteroid, run 10 or more with very slightly different
> starting parameters. If they stay clumped, try again, getting closer to
> the planet, or perhaps just simulate for more time.
Thanks again, it is great, but for one thing:
I did run another, with an orbit closer to Jupiter, but after a few
cycles it was ejected. I didn't like to mention that <grin>.
I then thought I would try ten asteroids, and clicked on new. That
wiped out all the data for all solar system planets, and restrarting
the system did not get them back. I have now installed the system
again but not tried any new experiments.
However "There are more things in heaven and earth, Horatio, than are
dreamt of in your philosophy."
William Shakespeare, "Hamlet", Act 1 scene 5
We now have three types of comet, Kuiper Belt, Oort Cloud, and Main
Belt. It is suspected that comets, when all their ice has been
sublimed away turn into earth crossing asteroids. We have asteroid,
which if they hit the earth are called meterorotes, and have dozens to
types http://www.meteoritemarket.com/type.htm
The thing is that the outer asteroids that are supposed to have
supplied Earth's oceans, are yet another type of asteroid. But they
may no longer exists since they crashed into Earth. This means we
cannot run the planetary simulator backwards and expect them to
reappear. We could run the simulator backwards and see where Jupiter
and Saturn were. But since the three body system is chaotic, then
further back we run it the less reliable would be the results. Since
we have to run it back to the beginning, then it is better to leave
that job to the professionals.
What they are saying is that about 3,800 million years ago Jupiter and
Saturn were in synchronous orbits which cause severe disruption to the
orbits of the outer asteroids. Their orbits would have changed from
simple ellipses to strange attractors. When the strange attractors
reached the Earth's orbit, the asteroids would be flying in parallel
with the Earth, and so a collision would be more likely than with an
earth crossing orbit. Of course for the asteroid to get there it would
have to miss Mars, and all the other asteroids, but this is not too
difficult because space vehicles have managed it.
You may have noticed that this is not what I said originally. I have
learnt a bit since then. Thanks!
Cheers, Alastair.
downloade t
>
> --
> Phil Hays <phil_h...@ieee.org>
Eric Swanson
al. and the follow on work by Swanson et al. (not me) don't predict or
explain the slight reduction in the rate of warming seen since the
rather warm year in 1998. Correlations between indices do not capture
the forcing. While some think otherwise, the NAO only captures the
pressure differences, not the cause of those pressure differences.
The changes in the Icelandic Low are the result of the storm paths,
not the cause of those storms moving closer to or farther away from
Iceland. From physics, the atmosphere, being a fluid, can not "pull",
only "push".
On Jan 9, 5:11 am, Robbo <rob...@robertellison.com.au> wrote:
> I think the evidence for climate shifts on decadal scales is evident
> in science of all sorts. Global shifts in temperature, rainfall, the
> 'Great Pacific Climate Shift' of 1976/1977, the instrumental
> temperature record. As indicated in the 2002 panel discussion of the
> National Academy. Tsonis et al have the virtue (in peer reviewed
> studies) of using numerical techniques to quantify. The numerical
> technique was not concerned with cause and effect - or cross
> correlation in the accepted sense - but in detecting patterns in
> signals. A network methodology as in the quote I provided earlier.
> Show me the papers disputing Tsonis - not simply your frankly silly
> claim that because they didn't factor out ENSO and volcanos from ENSO
> and other signals that the studies are invalidated.
The ENSO index is not a force, it's a result. Volcanos, solar
variability, AGE, the lunar cycle, are external forces. The changes
to the THC from AGW might also be considered "external" as in, Not
Natural.
> I sure I don't have a clue what you mean by 'speeding up'. The
> concept is that small changes in initial conditions triggers large
> flucuation in climate which then oscillates about a new state for a
> while. The oscillations tend to damp out (but not neccessarily)in
> complex systems providing a signal of the next shift.
There is evidence that the Antarctic Polar Vortex has increased in
strength, i.e., speeded up, as one result of ozone depletion. Also,
if the THC slows, it's likely that tropic to pole circulation would
increase to take up the slack in the tropic to pole heat transfer,
especially in winter.
> I link to the UNESCO site that provides ready access to indices that
> are updated by thousands of scientists around the world. And you
> simply accuse me of provising unjustified claims - a knee jerk no it
> just ain't so. Show me the science damn it.
OK, Here's a graph of the Winter NAO data from Hurrell plotted with a
curve from the application of an 11 year centered moving average:
http://i454.photobucket.com/albums/qq268/Know_body/NAO_Win1.jpg
And here's a cross plot of the two curves:
http://i454.photobucket.com/albums/qq268/Know_body/NAO_Win2.jpg
The straight line in this second graph is just the NAO curve plotted
against itself, ie., a 100% correlation. Notice how poorly the MA
follows the straight line. I'll leave it to you to do the correlation
calculation and explain why you think Tsonis' use of time series so
filtered is valid.
>...Your claim that these
> indices are not relevant because of global warming is unreflective
> nonsense. Somehow ENSO and the like have no relevance for
> understanding climate? Please.
Where did I claim that ENSO had no relevance for understanding
climate?? My claim was that the technique of Tsonis is not
predictive.
> You are just being foolish now.
No, I think you are grasping at straws. Anyway, here's a comment
regarding ENSO which just appeared. You can read the paper, if you
have AGU access.
http://dotearth.blogs.nytimes.com/2010/01/08/a-rebuttal-to-a-cool-climate-paper/
E. S.
---
Robbo
addressed in the peer reviewed literature - I am not aware of it and
you have not enlightened me. For one thing - Tsonis et al use NH
winter averages in an 11 year window - not an 11 year moving
average.
Let's have a look at SAM. The SAM index is on based on sea level
pressure (SLP)at a number of sub-Antactic sites. SLP is a function of
downwelling which in turn is dependent on UV warming of ozone in the
stratosphere. Higher temps produce less downwelling air feeding into
the polar vortex and thus lower SLP. So the SAM index captures some
pretty basic processes. The storm tracks in the SH are the result of
complex interactions of equatorial and sub-Antartic SLP.
But these are subsystems - of which there are legion - of what Tsonis
calls the grand climate system. Dynamical systems theory as applied
to climate is not concerned with forcings as such. Forcings of all
sorts are small changes in initial conditions that trigger large
changes in complex systems. It is not simple cause and effect - which
does not apply in the grand complex and dynamic climate system. We
are concerned with the behaviour of the system. Complex and dynamic
systems behave in certain ways - so if it is demonstrated that climate
behaves in the same ways at interannual to decadal and beyond scales
it provides a new way of analysing climate.
'Dynamical systems theory and chaos theory deal with the long-term
qualitative behavior of dynamical systems. Here, the focus is not on
finding precise solutions to the equations defining the dynamical
system (which is often hopeless), but rather to answer questions like
"Will the system settle down to a steady state in the long term, and
if so, what are the possible steady states?", or "Does the long-term
behavior of the system depend on its initial condition?"'
In this perspective, the current lack of warming is emergent behaviour
of climate as a dynamical complex system. It is a steady state that
tends to persist - qualitative behaviour - for a couple of decades
until perturbed by more small changes in initial conditions (or
climate forcings as they are known). I understand that people are
reluctant to accept a conclusion that is based on some fairly esoteric
science. Many activists would want to label me a 'denialist' and send
me to the salt mines. But it provides at least a metatheory for lack
of warming over the last decade - if the details are still very
unclear. And please - who was it in the leaked emails who said that
the lack of explanation for non warming was a
travesty?
Once the application of dynamical systems theory to climate is
understood it provides a new way of looking at climate that integrates
both forcings and dynamic Earth system responses.
> http://dotearth.blogs.nytimes.com/2010/01/08/a-rebuttal-to-a-cool-cli...
>
> E. S.
> ---
Eric Swanson
On Jan 9, 3:53 pm, Robbo <rob...@robertellison.com.au> wrote:
> If there are serious problems with the Tsonis methodology that are
> addressed in the peer reviewed literature - I am not aware of it and
> you have not enlightened me. For one thing - Tsonis et al use NH
> winter averages in an 11 year window - not an 11 year moving
> average.
From Tsonis et al. regarding Eqn 1:
"Here t denotes the time in the middle of a sliding window of
width Dt... Figure 1a shows the distance as a function of time for
a window length of Dt = 11 years"
A sliding window is the same as a centered moving average...
> Let's have a look at SAM. The SAM index is on based on sea level
> pressure (SLP)at a number of sub-Antactic sites. SLP is a function of
> downwelling which in turn is dependent on UV warming of ozone in the
> stratosphere. Higher temps produce less downwelling air feeding into
> the polar vortex and thus lower SLP. So the SAM index captures some
> pretty basic processes. The storm tracks in the SH are the result of
> complex interactions of equatorial and sub-Antartic SLP.
>
> But these are subsystems - of which there are legion - of what Tsonis
> calls the grand climate system. Dynamical systems theory as applied
> to climate is not concerned with forcings as such. Forcings of all
> sorts are small changes in initial conditions that trigger large
> changes in complex systems. It is not simple cause and effect - which
> does not apply in the grand complex and dynamic climate system. We
> are concerned with the behaviour of the system. Complex and dynamic
> systems behave in certain ways - so if it is demonstrated that climate
> behaves in the same ways at interannual to decadal and beyond scales
> it provides a new way of analysing climate.
Of course, the climate system exhibits chaotic behavior and may
exhibit periodic oscillatory behavior. But, at the risk of breaking
thru to your inner thoughts, that fact does not mean that changes in
climate can be predicted simply by looking at the various indices as
Tsonis et al. claim. Since there are other processes involved beyond
whatever dynamical system responses might obtain, looking at those
indices alone without considering the other forcings will provide
little useful information, since the oscillations are unlikely to be
periodic.
> 'Dynamical systems theory and chaos theory deal with the long-term
> qualitative behavior of dynamical systems. Here, the focus is not on
> finding precise solutions to the equations defining the dynamical
> system (which is often hopeless), but rather to answer questions like
> "Will the system settle down to a steady state in the long term, and
> if so, what are the possible steady states?", or "Does the long-term
> behavior of the system depend on its initial condition?"'
Neither question can be answered, since we can't start the real system
with a definitive set of initial conditions and assessing such
questions using data from the continually changing Earth is not likely
to be successful either. One can do experiments such as these with
computer models, but how can one be sure the results apply to the real
Earth? Or, if you agree the models are an accurate representation of
the Earth's climate, wouldn't you also accept the projections of
future climate based on such models?
> In this perspective, the current lack of warming is emergent behaviour
> of climate as a dynamical complex system. It is a steady state that
> tends to persist - qualitative behaviour - for a couple of decades
> until perturbed by more small changes in initial conditions (or
> climate forcings as they are known).
You assert without proof that the current lack of warming is the
result of internal system dynamics. Until you can provide such proof,
you are blowing smoke...
>...I understand that people are
> reluctant to accept a conclusion that is based on some fairly esoteric
> science. Many activists would want to label me a 'denialist' and send
> me to the salt mines. But it provides at least a metatheory for lack
> of warming over the last decade - if the details are still very
> unclear. And please - who was it in the leaked emails who said that
> the lack of explanation for non warming was a
> travesty?
That quote was taken from an e-mail by Trenberth and most reports by
the denialist camp have cherry picked the statement by taking it out
of context. Here's a link to the report with the original quote,
which I hope you will read.
http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/EnergyDiagnostics09final.pdf
BTW, I notice that there was no comment from you on the link to
today's NYT story. I guess you don't care about the ENSO.
> Once the application of dynamical systems theory to climate is
> understood it provides a new way of looking at climate that integrates
> both forcings and dynamic Earth system responses.
That's the problem, not the solution.
E. S.
---
Phil Hays
> I did run another, with an orbit closer to Jupiter, but after a few
> cycles it was ejected. I didn't like to mention that <grin>.
That's a good thing. A fair fraction of asteroids and comets get ejected
from the solar system, mostly because of interacting with Jupiter. A
couple of spacecraft have been ejected as well.
> I then thought I would try ten asteroids, and clicked on new. That
> wiped out all the data for all solar system planets, and restrarting
> the system did not get them back. I have now installed the system
> again but not tried any new experiments.
You should be able to load a data file. Some interesting data files to
load are at:
http://www.orbitsimulator.com/gravity/articles/simu.html
For example, to start with only the planets, load this file:
http://www.orbitsimulator.com/gravity/simulations/onlyplanets.gsim
> reached the Earth's orbit, the asteroids would be flying in parallel
> with the Earth, and so a collision would be more likely than with an
> earth crossing orbit.
Hmmm, I'm not sure if this claim is true or false. Remember that the
mostly likely interaction is a near passage, which will change the
orbit. This could change the orbit from a "earth crossing" to a "flying
in parallel" orbit, or the reverse. This would imply that perhaps there
wouldn't be much difference.
Mercury has a bunch of craters that seem to date to the late heavy
bombardment, so this would imply that Earth and Mars didn't stop all the
bodies. Venus as well.
> You may have noticed that this is not what I said originally. I have
> learnt a bit since then. Thanks!
You are very welcome, and thanks for listening.
--
Phil Hays <phil...@ieee.org>
Robbo
from others. They simply talk about natural and decadal vaiability
(duh)- and the lack of an adequate observing system. No need to get
defensive - it is just reality.
http://www.eastangliaemails.com/emails.php?eid=1048&filename=1255352257.txt
The answers can be approached with other mathematical techniques -
network (Tsonis) and autocorrelation (Dokas) techniques specifically.
Again, if you are aware of peer reviewed refutations of Tsonis -
please let me know.
I would copy the formula here but it is not reproducing well. The
paper can be found at: http://www.nosams.whoi.edu/PDFs/papers/tsonis-grl_newtheoryforclimateshifts.pdf)
The 11 year window is simply the interval, t - delta t/2, t delta t/2,
on which the 'distance' of the cross-correlation (yes but not causal)
of annual NH winter averages of the 4 indices (netwrok nodes) is
evaluated. It is not a moving average at all - it depends on
evaluating synchonous chaos on decadal scales and at specific
junctures - and this can't be done with a simple 11 average.
Synchonous chaos is evaluated at discrete timesteps in a sliding
window. It allows the assessment of climate shifts at around 1910,
the mid 1940's, the mid 1970's and 1998/2001 - very much in line with
the global temerature record. You can say it isn't so - but show me
the peer reviwed science.
I looked at the realclimate post on the study in your NYT link. It
addresses ENSO in passing in relation to ERBE global energy balances -
not relevant so I deliberately ignored it. I again can't see see what
your point is? That I don't care about ENSO? What does that mean?
> http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/EnergyDiagnost...
DrNickBone
> Nevertheless a the strong argument against it, as Robert Rohde
> mentioned, is that the Earth has been up to ~3000ppm in the past and
> recovered.
Though maybe it hasn't (at least not at all recently). See:
http://www.pnas.org/content/early/2009/12/24/0902323106.abstract
http://www.nature.com/news/2009/091230/full/news.2009.1168.html
Also discussed at:
http://scienceblogs.com/islandofdoubt/2010/01/is_the_earth_even_more_sensiti.php
By the way, what I'm getting from this thread is the following:
- Reasonable GCMs do sometimes show runaway warming
- Arguments that it could never happen (because of clouds etc.) are a
bit
"handwaving" in comparison
- Runaway warming could happen if the Earth's temperature gets above
300K
- That level of warming (about 13 degrees above pre-industrial) is a
stretch,
but not impossible if we push CO2 up to 4 x pre-industrial levels,
and then
add lots of feedbacks (like methane release)
- There is a historical argument that CO2 has been very high before,
without
triggering runaway, but apparently we can't be sure about that
either.
Not very reassuring I'm afraid.
Nick
Alastair
> Reasonable GCMs do sometimes show runaway warming
They show a fully cloud covered earth, similar to the outward state of
Venus, but they do not show a boiling away of the Earth's oceans.
> - Arguments that it could never happen (because of clouds etc.) are
> a bit "handwaving" in comparison
I cited a paper by Pierrehumbert which showed that a boiling away of
the oceans was not possible because the as the oceans boiled the
vapour pressure would increase the atmosphereic pressure so raising
the boiling point of the oceans.
> - Runaway warming could happen if the Earth's temperature gets above
> 300K
It is generally believed that if the global temperature rises by more
than 2K then that could be dangerous. But some island states are
pressing for a figure of 1.5K to be accepted, as even that could be
dangerous to them.
> - That level of warming (about 13 degrees above pre-industrial)
> is a stretch,
That has been seen in a very few models, but they could be right.
> but not impossible if we push CO2 up to 4 x pre-industrial levels,
> and then add lots of feedbacks (like methane release)
It seems likely that if we push CO2 high enough then we can get any
warming. The problem is that we won't stop pushing until it is obvious
it is too high, and by then it will be too late.
> - There is a historical argument that CO2 has been very high before,
> without triggering runaway, but apparently we can't be sure
> about that either.
We can be sure that CO2 has never been high enough to produce a Venus
effect, because if so we would not be here. Although, life does seem
to have survived Snowball Earth.
We do know that abrupt warmings have happened in the past, such as the
end of the Younger Dryas, and the PETM event.
What I am saying is that an abrupt climate change is a runaway event.
But it need not result in the Earth being in a similar state to
Venus. It is the term "runaway" which is confusing, and I have been
told not to use it, but I do because to me it means a positive
feedback of more than 1.
> Not very reassuring I'm afraid.
No it's not, even where I disagree with you.
Cheers, Alastair.
hgerh...@yahoo.co.uk
> the oceans was not possible because the as the oceans boiled the
> vapour pressure would increase the atmosphereic pressure so raising
> the boiling point of the oceans.
Very strictly speaking there is no boiling. Boiling is the formation
of bubbles of vapour in the water, because the pressure inside the
bubble is bigger than the pressure of the atmosphere. For a kettle
exposed to the open atmosphere, that external pressure stays constant
at 1 atmosphere. The water vapour released has no measurable impact on
the external pressure.
When the whole world warms to 100C, no bubbles with water vapour will
form in the ocean; rather the atmospheric pressure will go up to
around 2 atmospheres.
But that does not mean the water on Earth could not in its entirety
turn into vapour (though strictly speaking again, the 400 bar or so
implied from evaporating 4 km of ocean get us beyond the critical
point for water of 214 bar and 372C beyond which there is no phase
boundary between the liquid and gas phases of water)
> What I am saying is that an abrupt climate change is a runaway event.
> But it need not result in the Earth being in a similar state to
> Venus. It is the term "runaway" which is confusing, and I have been
> told not to use it, but I do because to me it means a positive
> feedback of more than 1.
Just talk about tipping points that result in Earth moving from one
stable equilibrium to another. Then people won't think you are talking
about Earth turning in Venus.
William Connolley
> On Jan 13, 10:41 am, DrNickBone <drnickb...@yahoo.co.uk> wrote:
>
>> Reasonable GCMs do sometimes show runaway warming
They show a fully cloud covered earth, similar to the outward state of
Venus, but they do not show a boiling away of the Earth's oceans.
{{cn}}, both of you.
-William
--
William M. Connolley | www.wmconnolley.org.uk | 07985 935400
Alastair
On Jan 14, 9:33 am, "hgerhau...@yahoo.co.uk" <hgerhau...@yahoo.co.uk>
wrote:
> > I cited a paper by Pierrehumbert which showed that a boiling away of
> > the oceans was not possible because the as the oceans boiled the
> > vapour pressure would increase the atmosphereic pressure so raising
> > the boiling point of the oceans.
>
> Very strictly speaking there is no boiling. Boiling is the formation
> of bubbles of vapour in the water, because the pressure inside the
> bubble is bigger than the pressure of the atmosphere. For a kettle
> exposed to the open atmosphere, that external pressure stays constant
> at 1 atmosphere. The water vapour released has no measurable impact on
> the external pressure.
>
> When the whole world warms to 100C, no bubbles with water vapour will
> form in the ocean; rather the atmospheric pressure will go up to
> around 2 atmospheres.
>
> But that does not mean the water on Earth could not in its entirety
> turn into vapour (though strictly speaking again, the 400 bar or so
> implied from evaporating 4 km of ocean get us beyond the critical
> point for water of 214 bar and 372C beyond which there is no phase
> boundary between the liquid and gas phases of water)
Yes you are correct. The oceans would not boil if the only heat was
from solar radiation. They would evaporate. But the issue is not
would they evaporate. It is would they evaporate completely as it is
surmised has happened on Venus. What I am saying is that this is not
possible because with such a high vapour density, the world would be
covered in cloud and the resulting albedo would reduce the solar
radiation that was causing the evaporation.
This also means that if Venus had the same amount of water as Earth
then it must have lost its water clouds to the solar wind.
> > What I am saying is that an abrupt climate change is a runaway event.
> > But it need not result in the Earth being in a similar state to
> > Venus. It is the term "runaway" which is confusing, and I have been
> > told not to use it, but I do because to me it means a positive
> > feedback of more than 1.
>
> Just talk about tipping points that result in Earth moving from one
> stable equilibrium to another. Then people won't think you are talking
> about Earth turning in Venus.
The problem is that there are two types of tipping point. The first
is when the overall feedbacks become positive, and the system is no
longer stable, and the second is when the positive feedback exceeds
100% and the system runs away. Thinking about positive feedbacks is
pretty muddled especially in the climate modeling community. For
instance Gavin Schmidt and William Connolley have tried to get each
other to correct Wikipedia. I don't dare do it, although I have
tried.
Cheers, Alastair.
matt andrews
> 2010/1/13 Alastair <a...@abmcdonald.freeserve.co.uk>:
>> On Jan 13, 10:41 am, DrNickBone <drnickb...@yahoo.co.uk> wrote:
>>
>>> Reasonable GCMs do sometimes show runaway warming
>
> They show a fully cloud covered earth, similar to the outward state of
> Venus, but they do not show a boiling away of the Earth's oceans.
>
> {{cn}}, both of you.
For those not familiar with the full gamut of Wikipedia template
shortcuts, William is invoking this:
http://en.wikipedia.org/wiki/Wikipedia:Citation_needed
Alastair
On Jan 14, 12:04 pm, matt andrews <wan...@gmail.com> wrote:
> 2010/1/14 William Connolley <wmconnol...@gmail.com>:
Journals don't publish papers from people whose models runaway, so I
doubt it is paper which I can cite even if I wanted to.
However, IIRC, http://climateprediction.net/ had some of their early
models, based on Hadley, running away and they became fully cloud
covered.
Cheers, Alastair.
DrNickBone
On 14 Jan, 09:44, William Connolley <wmconnol...@gmail.com> wrote:
> 2010/1/13 Alastair <a...@abmcdonald.freeserve.co.uk>:
>
> > On Jan 13, 10:41 am, DrNickBone <drnickb...@yahoo.co.uk> wrote:
>
> >> Reasonable GCMs do sometimes show runaway warming
>
> They show a fully cloud covered earth, similar to the outward state of
> Venus, but they do not show a boiling away of the Earth's oceans.
>
> {{cn}}, both of you.
>
> -William
I was referring to a comment by James Annan earlier in the thread
(post of 4th January)
>GCMs can achieve runaway warming - in fact some informal conversations
>suggest to me that this is rather more common than you might imagine
>based on reading the literature - but this is generally attributed to
>some nonphysical behaviour such as a parameterisation extrapolated
>beyond its valid range. However, I don't believe that Pierrehumbert's
>handwaving with simple approximations can really refute calculations of
>state of the art climate models.
I'm not sure which models James was thinking of. But if he is right
at least some have reached the literature, with others hiding in
the filedrawer marked "Uh-oh".
Personally, I'd consider it an academic point whether the oceans
literally boil away in these models, or the Earth comes back into
a new equilibrium with very high albedo. A cloud-covered Earth with
minimal or no life under the clouds is still an awful thought.
James Annan
I don't believe any have reached the literature, and none of them get
anywhere near boiling point, the models crash at much cooler temperatures.
Um....if you really need a citation, some are mentioned in
http://www.clim-past.net/5/803/2009/cp-5-803-2009.html
It is not just the perturbed parameter stuff that does this, "ordinary"
models sometimes manage it while under development, or under very high CO2.
Righty or wrongly, it seems that no-one takes it seriously in physical
terms. I expect if cpdn had found models like this it would have been
headline news, but they only found spurious cooling which was
"obviously" unphysical :-)
James
Per Edman
<a...@abmcdonald.freeserve.co.uk> wrote:
>>>> Reasonable GCMs do sometimes show runaway warming
> Journals don't publish papers from people whose models runaway, so I
> doubt it is paper which I can cite even if I wanted to.
That could be a very convenient explanation to some. Well then, can you
cite an unpublished paper? Anything would be better than nothing, I think.
> However, IIRC, http://climateprediction.net/ had some of their early
> models, based on Hadley, running away and they became fully cloud
> covered.
Any idea what I could look for to find those models?
Was it perhaps one of these:
http://climateprediction.net/content/millennium-experiment-famous ?
I'm running Climateprediction myself and if I reason correctly, it would
only make sense that some early calibration models WOULD run away, or run
down, until reasonable parameters were found. Bruteforce is still a
workable method. The model I'm currently running, however, is not 100%
cloud covered at 800C.
Thanks!
/ Per
--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/
DrNickBone
>
> Um....if you really need a citation, some are mentioned in
>
> http://www.clim-past.net/5/803/2009/cp-5-803-2009.html
>
Thanks for this. This part of your paper jumped out at me:
>For the doubled CO2 experiment a number of the ensemble
>members with higher control temperature and high sensitivity
>became unstable once the global mean surface temperature
>exceeded 296 K.
That 296K seems close to the ~300K mentioned above by hgerhauser
(post of 7th January). I also found this: magic number
of 300K (27 degrees C) appears again...
http://earthobservatory.nasa.gov/Newsroom/view.php?id=22423
And again here...
http://geo.arc.nasa.gov/sgp/radiation_aug01/rad7.html
>Surprisingly, above 300K the outgoing radiation emitted to space >actually decreases with rising SST. Less energy to space implies >that more energy is available to heat the surface, leading to a >potentially unstable situation. This behavior is a signature of >the runaway greenhouse effect on Earth.
The overall picture seems consistent here.
- Combination of high CO2 or high sensitivity, or
carbon/methane feedbacks, or all three, could
take us up to 300K
- At that temperature, runaway warming is a real danger
- We don't know exactly what the end-point is like
(models blow up), but it's not pretty: Earth doesn't
look habitable anymore.
Hansen might be wrong in the details, but he's right to get the
discussion out of the closet.
Nick
Alastair
On Jan 15, 11:35 am, "Per Edman" <per.piotrr.ed...@gmail.com> wrote:
> On Thu, 14 Jan 2010 17:40:51 +0100, Alastair
>
> Any idea what I could look for to find those models?
> Was it perhaps one of these: http://climateprediction.net/content/millennium-experiment-famous?
>
> I'm running Climateprediction myself and if I reason correctly, it would
> only make sense that some early calibration models WOULD run away, or run
> down, until reasonable parameters were found. Bruteforce is still a
> workable method. The model I'm currently running, however, is not 100%
> cloud covered at 800C.
It was the earliest model which had a bug where the slab ocean was
mishandling the Humboldt Current - a sort of super El Nino.
The catch is, because those models runs were faulty, they were thrown
away! (Sort of like the original satellite measurements of the ozone
hole!)
I can't believe that your model is running with a global average
temperature of 800 C, or even 800 K. At 80C I would have expected
total cloud cover but it possible that the condensation level at that
temperature is too high for clouds to form. But at what temperature
and whether a model shows total cloud would depend on how it is
constructed. We have no guarantee that the model would reflect
reality either way. We do, of course, know that Venus it totally cloud
covered, so there is evidence that it can happen.
But at present I only have strong grounds for believing that at a high
enough surface temperature the earth would be cloud covered. I cannot
prove it.
Cheers, Alastair.
James Annan
> On Thu, 14 Jan 2010 17:40:51 +0100, Alastair
> <a...@abmcdonald.freeserve.co.uk> wrote:
>
>>>>> Reasonable GCMs do sometimes show runaway warming
>
>> Journals don't publish papers from people whose models runaway, so I
>> doubt it is paper which I can cite even if I wanted to.
>
> That could be a very convenient explanation to some. Well then, can you
> cite an unpublished paper? Anything would be better than nothing, I think.
>
Did you not read my previous message? We've seen it in several of our
model runs, and explicitly mention it in publications. I'm not sure why
you are effectively claiming I'm making it up...
I know of an ultra-hi-res cloud-resolving model here that had negative
radiative feedback (it was coupled to a fixed SST so was not able to run
away).
James
James Annan
> James,
>
>> Um....if you really need a citation, some are mentioned in
>>
>> http://www.clim-past.net/5/803/2009/cp-5-803-2009.html
>>
>
> Thanks for this. This part of your paper jumped out at me:
>
>> For the doubled CO2 experiment a number of the ensemble
>> members with higher control temperature and high sensitivity
>> became unstable once the global mean surface temperature
>> exceeded 296 K.
>
> That 296K seems close to the ~300K mentioned above by hgerhauser
> (post of 7th January).
Yes, I'd noticed the interesting coincidence. However, it may just be a
model quirk. Once the atmosphere is that much warmer, the structure has
may have changed sufficiently that the assumptions that went into the
model may not be valid. Specifically, whe discussing this with others, I
have heard people suggest that the ozone in the upper atmosphere may end
up misplaced relative to the (new) atmospheric structure. But I don't
know anything about this. Maybe I should look into it since we have
several runaway models.
Google finds this, don't think anyone has mentioned it.
James
Per Edman
>> The model I'm currently running, however, is not 100%
>> cloud covered at 800C.
> I can't believe that your model is running with a global average
> temperature of 800 C, or even 800 K. At 80C I would have expected
My apologies for my poor sentence structure. That's exactly why the model I'm currently running is NOT 100% cloud covered, or at 800C. Quite the opposite, my model is running at an expected temperature in a completely realistic 1 atm.
Interesting this, would be amazing if one could modify the source data oneself, but that would probably defeat the purpose of a distributed computing grid.
--
/ Per
Per Edman
I'm not claiming you're making it up. At worst, I'm trying to point out the need for sources or even attempting to provoke you into providing some. :) No implication intended, it was a careless musing.
--
/ Per
Alastair
> http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%...
>
> James
That link is interesting. I think they are saying when the solar
constant, currently equal to 1450 Wm-2 reaches 1600 Wm-2 in
1,000,000,000 years time then bye bye. However, in the abstract they
state:
"The calculated values of the upper limit of radiation and water vapor
content cannot be
directly applied to describing real planetary atmospheres, since the
model physical processes are quite simple—
gray radiation scheme without clouds."
But we know that the atmosphere is not gray. It is banded. Moreover,
my idea that the clouds would set a new TOA balance, cannot be tested
with that system since there are none!
What we need is not a system that just runs away, but one that runs
away to a new stable state.
Cheers, Alastair.
hgerh...@yahoo.co.uk
>
That's where I got the 300K from.
300K also nicely fits with paleo evidence, ie it's very much at the
high end of what's credible for past climates. So if we get there,
past climates can no longer be used to argue that runaway is not
credible.
Alastair
I tried to get hold of the source code and was blocked, but if you
appealed using the Freedom of Information Act you might be more
successful! In fact the PUM is available from the Met Office if you
can give a good academic reason.
http://www.metoffice.gov.uk/science/creating/daysahead/nwp/um.html
but you need good visualisation software for clouds, which I think was
specially developed by Climate Prediction.
The source code for the Community Climate Model is also available.
http://www.cgd.ucar.edu/cms/ccm3/
There is also a simpler model here:
http://www.mi.uni-hamburg.de/PUMA.215.0.html?&L=3
and here:
http://www.mi.uni-hamburg.de/Planet-Simul.216.0.html?&L=3
Cheers, Alastair.
Per Edman
> On Jan 15, 7:39 pm, "Per Edman" <per.piotrr.ed...@gmail.com> wrote:
>> My apologies for my poor sentence structure. That's exactly why the model I'm currently running is NOT 100% cloud covered, or at 800C. Quite the opposite, my model is running at an expected temperature in a completely realistic 1 atm.
>>
>> Interesting this, would be amazing if one could modify the source data oneself, but that would probably defeat the purpose of a distributed computing grid.
> I tried to get hold of the source code and was blocked, but if you
> appealed using the Freedom of Information Act you might be more
> successful! In fact the PUM is available from the Met Office if you
> can give a good academic reason.
> http://www.metoffice.gov.uk/science/creating/daysahead/nwp/um.html
> but you need good visualisation software for clouds, which I think was
> specially developed by Climate Prediction.
I meant, if one was able to select the input dataset ("source data", not the source code) for the ClimatePredition.net application, THAT could be used to answer questions such as this. The model really is rather accurate.
Alastair
Precise, yes! Accurate, how do you know?
Anyway, if you want to play with data then try EdGCM
http://edgcm.columbia.edu/spotlight-o/edgcm-project-overview/
Cheers, Alastair.
Per Edman
<a...@abmcdonald.freeserve.co.uk> wrote:
> On Jan 17, 12:22 pm, "Per Edman" <per.piotrr.ed...@gmail.com> wrote:
>> On Sat, 16 Jan 2010 12:24:46 +0100, Alastair
>> <a...@abmcdonald.freeserve.co.uk> wrote:
>> > On Jan 15, 7:39 pm, "Per Edman" <per.piotrr.ed...@gmail.com> wrote:
>> I meant, if one was able to select the input dataset ("source data",
>> not the source code) for the ClimatePredition.net application, THAT
>> could be used to answer questions such as this. The model really is
>> rather accurate.
> Precise, yes! Accurate, how do you know?
Accurate because when the model runs for historical years, its data
corresponds to known data for those years. You could consider that
calibration, of course, but once the model runs as the climate has
actually run for the past years in the simulation, you would have to come
up with reasons why model and reality would drastically diverge at exactly
the current date.
I currently have models at years 1820, 1988 and 2000, running from earlier
data. If those models correspond to recorded history, I consider that a
calibration that results in an accurate model. The more runs, the more it
gets corrected, the more accurate it gets.
> Anyway, if you want to play with data then try EdGCM
> http://edgcm.columbia.edu/spotlight-o/edgcm-project-overview/
Interesting, thanks.
hgerh...@yahoo.co.uk
> corresponds to known data for those years. You could consider that
> calibration, of course, but once the model runs as the climate has
> actually run for the past years in the simulation, you would have to come
> up with reasons why model and reality would drastically diverge at exactly
> the current date.
Considering that the forcings are so poorly known, particularly
aerosols, the calibration is awfully poor.
So why might the model and reality diverge at exactly the current
date? Because the model can be made to agree with reality up to
exactly the current date by fiddling with the assumed forcing input.
You should be aware of the fact that there are plenty of models that
agree well with the past up to "exactly the current date" and then
diverge from each other.
Besides, this thread is about runaway warming and therefore about
conditions far removed from the calibration period.
Per Edman
> So why might the model and reality diverge at exactly the current
> date? Because the model can be made to agree with reality up to
> exactly the current date by fiddling with the assumed forcing input.
Are you sure what you're speculating about? The distributed computing
client receives seed data and runs a model based on starting parameters.
It is not modified with additional data while it runs. So I don't believe
I'm convinced that such a model would likely diverge at the current date.
> Besides, this thread is about runaway warming and therefore about
> conditions far removed from the calibration period.
True. As you move further away from the starting point, divergences
reinforce each other.
hgerh...@yahoo.co.uk
> client receives seed data and runs a model based on starting parameters.
> It is not modified with additional data while it runs. So I don't believe
> I'm convinced that such a model would likely diverge at the current date.
The problem is that the forcing isn't known well for the 20th century.
That's why climate sensitivity is not well constrained by 20th century
data.
The only way to make model runs of the 20th century closely match
reality is by choosing corresponding forcings, that is for high
climate sensitivity high aerosol forcing, and for low climate
sensitivity low aerosol forcing.
http://climateprediction.net/content/public-presentations-talks-and-posters
(Myles Allen, What can be said about future climate? Quantifying
uncertainty in multi-decade climate forecasting, Harvard University,
February 2008.) slide 7
Alastair
On Jan 19, 6:22 pm, "hgerhau...@yahoo.co.uk" <hgerhau...@yahoo.co.uk>
wrote:
> > Are you sure what you're speculating about? The distributed computing
> > client receives seed data and runs a model based on starting parameters.
> > It is not modified with additional data while it runs. So I don't believe
> > I'm convinced that such a model would likely diverge at the current date.
>
> The problem is that the forcing isn't known well for the 20th century.
> That's why climate sensitivity is not well constrained by 20th century
> data.
>
> The only way to make model runs of the 20th century closely match
> reality is by choosing corresponding forcings, that is for high
> climate sensitivity high aerosol forcing, and for low climate
> sensitivity low aerosol forcing.
>
> (Myles Allen, What can be said about future climate? Quantifying
> uncertainty in multi-decade climate forecasting, Harvard University,
> February 2008.) slide 7
Per,
Let me put it aother way.
You are correct that the ClimatePrediction models are not tweaked
during the initial phase to make them match the current climate, but
if at the end of that run they do not match then they are discarded,
and the second phase is aborted. So effectively, they are using
tweaked parameters - ones that fit the current climate.
The results from the third phase vary by a large degree, despite the
fact that they the models have been selected. They range from 1.5C to
over 10.0C, so since only one correct answer, there must be an awful
those models giving the wrong answer.
Cheers, Alastair.